Reverse salient pole permanent magnet auxiliary synchronous reluctance motor with composite magnetic barrier

Abstract

The invention discloses a reverse salient pole permanent magnet auxiliary synchronous reluctance motor with a composite magnetic barrier. The motor adopts a 54-slot 8-pole matched double-layer distributed stator winding. The rotor is of a reverse salient pole structure and is provided with eight semicircular salient poles protruding towards the circle center. Two layers of arc-shaped magnetic barriers facing the stator are arranged in each salient pole, the middle part of the inner-layer magnetic barrier is broken, and the outer-layer magnetic barrier is continuous; a rectangular permanent magnet containing groove is formed between every two adjacent salient poles, and a mixed permanent magnet formed by stacking neodymium iron boron and samarium cobalt permanent magnets is placed in each groove. Irregular circular magnetic barriers are arranged at the two ends of the accommodating groove and are connected with the two ends of the inner-layer disconnected magnetic barrier; 54 circular cooling channels are uniformly distributed in the stator yoke part and the rotor in the circumferential direction. Through the unique composite magnetic barrier and reverse salient pole rotor topology, the hybrid permanent magnet and the double-circulation cooling system, a magnetic circuit and a thermal circuit are cooperatively optimized, the salient pole rate, the torque density and the power factor of the motor are effectively improved, the torque pulsation is remarkably inhibited, and the heat dissipation performance and the demagnetization tolerance are enhanced.

Description

Technical Field

[0001] This invention relates to the field of synchronous motor technology, specifically to a permanent magnet assisted synchronous reluctance motor, and more particularly to a permanent magnet assisted synchronous reluctance motor that adopts a novel composite magnetic barrier and anti-salient pole rotor topology and integrates a high-efficiency cooling system. Background Technology

[0002] The working principle of a synchronous reluctance motor is based on the reluctance torque principle, and its output torque is proportional to the inductance difference (Ld-Lq) between the direct axis (d-axis) and the quadrature axis (q-axis). The rotor of this motor is made solely of stacked silicon steel sheets. By designing a specific magnetic barrier structure, a significant difference in reluctance can be created between the d-axis and q-axis magnetic circuits. Since the rotor does not require permanent magnets or electrically excited windings, synchronous reluctance motors offer advantages such as simple structure, low manufacturing cost, robustness, reliability, zero rotor copper loss, and high efficiency potential. Permanent magnet assisted synchronous reluctance motors embed an appropriate amount of permanent magnets (such as ferrite) into the magnetic barriers of the synchronous reluctance motor rotor. By utilizing the permanent magnet flux linkage to adjust the d-axis magnetic field, the power factor, torque density, and efficiency are effectively improved, allowing it to maintain its cost advantage while achieving performance closer to that of a permanent magnet synchronous motor.

[0003] Despite the advantages mentioned above, synchronous reluctance motors and permanent magnet assisted synchronous reluctance motors still face several technical bottlenecks in practical applications. Torque density is limited by the maximum saliency ratio (Lq / Ld) achievable by the rotor structure. Traditional designs increase the saliency ratio by increasing the number of magnetic barrier layers or optimizing the barrier shape. However, when the number of barrier layers exceeds three, the effect on improving the saliency ratio becomes insignificant. Instead, the thin magnetic bridge weakens the rotor's mechanical strength, increasing the risk of high-speed operation. Furthermore, the complex multi-layered magnetic barriers increase the design and manufacturing difficulty of the lamination molds. Under high load conditions, the motor power factor is typically below 0.9. The large reactive current not only increases the inverter capacity but also increases system losses. In addition, the reluctance torque varies periodically with the rotor position, and coupled with the influence of air gap magnetic field harmonics, torque ripple is usually large, reaching 10%-15% of the average torque, affecting the smoothness and quietness of motor operation.

[0004] Existing rotor magnetic barrier structures vary, but each has its limitations. C-shaped magnetic barriers, by forming an arc-shaped magnetic reluctance barrier on the rotor's outer periphery, can improve the Ld-Lq difference while maintaining ease of manufacturing. However, the flux concentration of a single-layer C-shaped magnetic barrier is limited, making it difficult to further increase torque density. Multi-layer arc-shaped magnetic barriers, with 2-5 layers stacked within the same pole and connected by magnetic bridges to form a larger magnetic reluctance difference, can improve torque density and power factor. However, the multi-layer structure increases the processing steps and the difficulty of manufacturing magnetic bridges, and the thickness of the magnetic bridges is detrimental to heat dissipation. U-shaped or irregular magnetic barriers suppress specific torque harmonics through asymmetrical design, but often result in a decrease in average torque, leading to a compromise in overall performance. S-shaped magnetic flux paths, formed by alternating strong and weak magnetic reluctance sides, can reduce torque pulsation, but require higher precision in the magnetic bridges, significantly increasing manufacturing costs.

[0005] Heat dissipation performance is a key factor affecting motor reliability. The efficiency of self-fan cooling or natural ventilation is limited by ambient temperature and speed, making it difficult to meet the heat dissipation requirements of high power density, especially in the permanent magnet region inside the rotor. While rotor oil cooling or shaft oil cooling can directly cool the rotor interior, it requires complex rotary sealing joints, oil pumps, and external cooling systems, increasing mechanical complexity and maintenance costs. Water cooling primarily targets stator cooling, offering limited effectiveness in cooling hot spots inside the rotor, and increases system weight and sealing requirements. Hybrid cooling solutions, while theoretically balancing efficiency and cost, lack mature industrial implementation options.

[0006] Based on the aforementioned technical background, this invention aims to comprehensively improve torque density, power factor, operational stability, and heat dissipation reliability through innovative rotor topology and cooling design, without significantly increasing manufacturing costs and structural complexity. Specifically, the technical problems this invention addresses include: how to further increase the salient pole ratio and reluctance torque to improve power factor and efficiency; how to optimize the matching of permanent magnet torque and reluctance torque to increase average torque while suppressing torque ripple; how to design efficient heat dissipation paths, particularly for cooling the permanent magnet region inside the rotor, to prevent high-temperature demagnetization; and how to control manufacturing costs and process complexity while ensuring excellent electromagnetic performance. Summary of the Invention

[0007] This invention aims to address the technical problems existing in current permanent magnet assisted synchronous reluctance motors in terms of electromagnetic performance, torque quality, heat dissipation, and manufacturing cost. Specifically, this invention aims to achieve the following technical objectives without significantly increasing structural complexity and manufacturing costs: Firstly, by optimizing the rotor magnetic barrier topology, the salient pole ratio and reluctance torque of the motor are further improved, thereby improving the power factor and efficiency. Secondly, by rationally designing the matching relationship between the permanent magnet and the magnetic barrier, the phase and amplitude of the permanent magnet torque and the reluctance torque are well matched, improving the average torque output. Thirdly, by improving the cooling system design, especially the heat dissipation path in the permanent magnet region inside the rotor, the rotor temperature rise is effectively controlled, preventing high-temperature demagnetization of the permanent magnet and ensuring the reliability of the motor during continuous operation under high load. Finally, while achieving the above performance improvements, the invention maintains the feasibility and economy of the structure, ensuring that the technical solution has industrial application value.

[0008] The specific plan is as follows: The present invention provides an anti-salient pole permanent magnet assisted synchronous reluctance motor with composite magnetic barriers, comprising a stator, a rotor and a shaft arranged sequentially from the outside to the inside.

[0009] The stator is made of 54 slot laminations, with 54 stator slots formed circumferentially on its inner side. Double-layer short-pitch distributed windings (three-phase symmetrical windings, using a star connection) are embedded in the slots to optimize the magnetomotive force waveform. On the periphery of the stator yoke, 54 first circular cooling channels that penetrate the length of the iron core are evenly opened circumferentially to form a stator-side cooling circuit.

[0010] The rotor is the core innovative component. Its outer circumferential contour is an anti-salient pole structure, that is, it has eight semi-circular salient poles protruding towards the rotor center (evenly distributed along the circumference), which is the opposite of the traditional outward salient pole structure. Inside each semi-circular salient pole, two concentric arc-shaped air magnetic barriers (or filled with non-magnetic material) are stamped to form a gap in the middle of the inner arc-shaped magnetic barrier, while the outer arc-shaped magnetic barrier remains continuous and uninterrupted, and the two magnetic barriers have the same thickness.

[0011] On the circumference of the rotor, a rectangular permanent magnet receiving slot is provided between two adjacent semi-circular salient poles, totaling eight; each receiving slot contains a hybrid permanent magnet, which is composed of at least one thick neodymium iron boron (NdFeB) permanent magnet layer and at least one thin samarium cobalt (SmCo) permanent magnet layer tightly stacked (adhesive or mechanically fixed) along the thickness direction. The neodymium iron boron layer provides high magnetic energy product, and the samarium cobalt layer provides high temperature resistance and stability.

[0012] Furthermore, at each end of the width of each rectangular permanent magnet receiving slot, an irregularly shaped circular end magnetic barrier is formed. This end magnetic barrier does not exist in isolation; its two ends are connected to the nearest arc-shaped magnetic barrier in the inner layer of the rotor located on the stator side of the permanent magnet. This connection structure enables the arc-shaped magnetic barrier, the irregularly shaped circular end magnetic barrier, and the permanent magnet slot to form a complex and efficient composite magnetic barrier network for precise guidance and control of the magnetic flux path.

[0013] In addition, 54 second circular cooling channels, extending through the length of the core, are uniformly arranged circumferentially inside the rotor core, in the area between all magnetic barriers and the rotor shaft, forming a rotor-side cooling circuit. The axes of both the first and second circular cooling channels are parallel to the axis of the rotor shaft, and both channels are used to circulate a cooling medium (air, oil, or a water-glycol mixture).

[0014] Compared with the prior art, the anti-salient pole permanent magnet assisted synchronous reluctance motor with composite magnetic barriers provided by the present invention has the following significant advantages and beneficial effects: 1. This invention achieves comprehensive optimization of the electromagnetic performance of the motor through a unique anti-salient pole rotor structure and composite magnetic barrier design. The anti-salient pole structure forms eight semi-circular salient poles protruding towards the center on the outer edge of the rotor. Combined with a double-layered arc-shaped magnetic barrier with an inner layer that is disconnected and an outer layer that is continuous, and the connection design between the irregular circular end magnetic barriers at both ends of the permanent magnet accommodating slot and the disconnection points of the inner magnetic barriers, a highly efficient and balanced composite magnetic barrier network is constructed. Experimental data shows that this structure improves the motor's power factor, while significantly increasing the proportion of reluctance torque, effectively reducing the excitation current demand and alleviating the inverter's burden.

[0015] 2. Another significant advantage of this invention lies in achieving a synergistic improvement in both high torque density and low torque ripple. By stacking neodymium iron boron (NdFeB) and samarium cobalt (SMC) permanent magnets to form a hybrid permanent magnet, and optimizing its arrangement angle and magnetization direction in the rotor, the phase and amplitude of the permanent magnet torque and reluctance torque are optimally matched. The precise modulation of the air gap magnetic field by the composite magnetic barrier network makes the air gap magnetic flux density waveform more sinusoidal, effectively suppressing torque harmonics of specific orders. This significantly improves the smoothness and quietness of motor operation, meeting the stringent torque quality requirements of high-end applications such as electric vehicle main drives and precision servo systems.

[0016] 3. This invention achieves a breakthrough improvement in heat dissipation performance. By uniformly distributing 54 first circular cooling channels circumferentially in the stator yoke and 54 second circular cooling channels circumferentially in the region between the magnetic barrier and the rotor shaft inside the rotor, an independent and highly efficient dual-circulation cooling system is constructed. The stator cooling channels directly cool the winding ends and core hot spots, while the rotor cooling channels penetrate the area behind the permanent magnet housing slots, effectively removing heat generated by rotor iron losses and permanent magnets. This built-in cooling design eliminates the need for complex rotary seals or external pumping systems, maintaining a simple structure while reducing the maximum temperature rise inside the rotor, ensuring the magnetic performance stability of the NdFeB permanent magnets under high-temperature conditions, and significantly improving the reliability of the motor during continuous high-load operation. In particular, the geometry of the circular cooling channels has excellent flow characteristics and media adaptability, allowing for forced liquid cooling with water or a water-glycol mixture, or the selection of oil, air, or other cooling media depending on the application scenario, providing flexibility and scalability for heat dissipation solutions under different operating conditions and environments.

[0017] 4. The rotor structure of this invention achieves high performance while also considering the feasibility and economy of manufacturing processes. Although the composite magnetic barrier shape is highly functional, its geometric features are all formed in one step through stamping, requiring no additional processing steps. The hybrid permanent magnet scheme uses a small amount of high-cost samarium cobalt permanent magnets in combination with a large amount of relatively economical neodymium iron boron permanent magnets, ensuring high-temperature stability while controlling material costs. The anti-salient pole structure enhances the rotor's mechanical integrity, optimizing the magnetic bridge thickness, ensuring mechanical strength while reducing core losses. The overall design improves electromagnetic performance while fully considering the feasibility and cost-effectiveness of large-scale production, demonstrating good industrialization prospects.

[0018] 5. The magnetic field distribution of this invention has been carefully optimized, effectively improving material utilization and energy conversion efficiency. As shown in the magnetic field lines diagram and magnetic flux density cloud diagram, the composite magnetic barrier network can effectively constrain the permanent magnet flux, reduce magnetic leakage, and guide the flux to the air gap in a more concentrated and sinusoidal manner. This not only improves the utilization rate of the permanent magnet but also reduces local magnetic flux density saturation and harmonic content in the iron core, helping to reduce iron core losses and electromagnetic noise. The optimized magnetic field distribution makes the electromagnetic design of the motor more balanced, further improving the overall performance indicators.

[0019] In summary, this invention, through the innovative synergistic design of composite magnetic barriers and anti-salient pole rotor topology, hybrid permanent magnet configuration, and built-in dual-cycle cooling system, maintains the inherent advantages of permanent magnet assisted synchronous reluctance motors such as simple structure and controllable cost, while comprehensively improving torque density, power factor, efficiency, torque quality, and heat dissipation reliability. It provides a highly competitive high-performance motor solution for fields such as new energy vehicles and high-end industrial drives. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the axial cross-sectional structure of the motor according to an embodiment of the present invention.

[0021] Figure 2 for Figure 1 The enlarged half-view of the rotor section highlights the composite magnetic barrier structure, the permanent magnet accommodating slot, and their connection relationships. It should be noted that this view does not include the second circular cooling channel on the rotor side, although the second circular cooling channel on the rotor side is installed inside the rotor.

[0022] Figure 3 This is a schematic diagram of the magnetic field distribution of the motor of the present invention under rated load conditions.

[0023] Figure 4 This is a flux density cloud diagram of the motor of the present invention under rated load conditions.

[0024] Figure 5 This is a comparison curve of the output torque of the motor of the present invention and a conventional permanent magnet assisted synchronous reluctance motor as a function of time.

[0025] Figure 6 This is a waveform diagram of the radial component of the air gap magnetic flux density of the motor of the present invention under no-load conditions.

[0026] List of reference numerals in the attached diagram: 1-Stator core; 2-Double-layer short-pitch distributed winding; 3-First circular cooling channel; 4-Rotor core; 5-Shaft; 6-Semi-circular salient pole; 7-Inner layer arc-shaped magnetic barrier (disconnected in the middle); 8-Outer layer arc-shaped magnetic barrier (continuous); 9-Permanent magnet receiving slot; 10-NdFeB permanent magnet layer; 11-Samarium cobalt permanent magnet layer; 12-Irregular circular end magnetic barrier; 13-Second circular cooling channel. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0028] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a 54-slot 8-pole permanent magnet assisted synchronous reluctance motor. The stator core 1 is made of high-grade silicon steel sheets stacked together, and 54 pear-shaped slots are formed on its inner side. Three-phase symmetrical double-layer short-pitch distributed stator windings 2 are embedded in the slots. Near the outer circle of the yoke of the stator core 1, 54 through holes are uniformly machined circumferentially to form the first circular cooling channel 3 on the stator side, which is used to introduce a cooling medium, such as air, oil, or a water-glycol mixture.

[0029] The rotor core 4 is made of high-permeability, low-loss cold-rolled non-oriented silicon steel sheets through stamping and stacking processes, and is reliably fixed to the shaft 5 by key connection. The outer edge contour of the rotor core adopts an anti-salient pole design, with eight semi-circular salient poles 6 evenly distributed circumferentially towards the rotor center. The geometric center line of each semi-circular salient pole 6 coincides with the rotor pole center line. The radius and height of the salient pole are determined by comprehensive optimization of electromagnetic performance and mechanical strength, ensuring that sufficient magnetic circuit cross-sectional area is provided while maintaining the structural rigidity and dynamic balance performance of the rotor.

[0030] Inside each semi-circular salient pole 6, two layers of air magnetic barriers are formed in one piece using a high-precision stamping process: an inner arc-shaped magnetic barrier 7 and an outer arc-shaped magnetic barrier 8. Both layers of magnetic barriers are concentric arcs, with their centers coinciding with the rotor's center. The arc length and angle are rationally designed based on the pole arc coefficient and magnetic circuit optimization requirements. The inner arc-shaped magnetic barrier 7 employs a broken structure at its arc geometric center, forming two symmetrically distributed arc segments. The width of the break is determined through magnetic circuit simulation optimization to ensure low magnetic reluctance characteristics of the d-axis magnetic circuit. The outer arc-shaped magnetic barrier 8 is a continuous and complete arc structure without any breaks. The radial spacing and axial thickness of the two layers of magnetic barriers are both designed in a balanced manner based on the feasibility of the stamping process and the requirements of magnetic circuit performance, ensuring good process feasibility while meeting electromagnetic performance requirements. The openings of both layers of magnetic barriers face the stator side, forming an optimized magnetic circuit fit with the stator tooth structure to jointly construct a highly efficient composite magnetic barrier network.

[0031] In the circumferential direction, a rectangular permanent magnet receiving groove 9 is provided between every two adjacent semi-circular convex poles 6. In this embodiment, a total of eight such grooves are provided. A thin layer of samarium cobalt permanent magnet 11 and a thick layer of neodymium iron boron permanent magnet 10 are installed in sequence in each groove. The two are closely attached and fixed by adhesive or structural components to form an integral hybrid permanent magnet block.

[0032] The key feature is that each end of the permanent magnet receiving groove 9 extends into an irregularly shaped circular end magnetic barrier 12 with optimized design along its width. The ends of these irregularly shaped circular end magnetic barriers 12 are not suspended, but are firmly connected to the nearest disconnected endpoint (i.e., the break point) of the inner arc-shaped magnetic barrier 7. This connection allows the magnetic flux generated by the permanent magnet to be precisely guided and redistributed through the break point between the irregularly shaped circular end magnetic barrier 12 and the inner arc-shaped magnetic barrier 7, which is the core design element for forming the composite magnetic barrier network and optimizing the magnetic circuit.

[0033] In the internal region of the rotor core 4, that is, the part of the core between the inner side of all magnetic barriers (7, 8, 12) and the shaft 5, 54 rotor-side second circular cooling channels 13 are evenly opened in the circumference. These channels work together with the stator-side first circular cooling channels 3 to form a highly efficient double-sided cooling system.

[0034] Figure 3This is a diagram showing the magnetic flux distribution of the motor of the present invention under rated load conditions. It can be clearly observed from the diagram that the magnetic flux generated by the permanent magnet originates from the N pole, passes through the air gap, enters the stator teeth, and closes at the stator yoke to form a complete magnetic circuit. The armature reaction magnetic field generated by the armature current and the permanent magnet magnetic field are superimposed to form a composite magnetic field distribution.

[0035] The difference in magnetic circuit characteristics can be clearly seen from the distribution density of magnetic field lines: the q-axis magnetic circuit passes through the semi-circular salient pole 6, and then successively passes through the outer arc-shaped magnetic barrier 8 and the inner arc-shaped magnetic barrier 7. The magnetic field lines in this region are sparse and light in color, indicating low magnetic flux density and significantly increased magnetic reluctance. The d-axis magnetic circuit mainly passes through the break in the inner arc-shaped magnetic barrier 7, the irregular circular end magnetic barrier 12, and the iron core bridges on both sides of the permanent magnet receiving slot 9. The magnetic field lines in this region are dense and dark in color, indicating high magnetic flux density and relatively low magnetic reluctance. This large difference in magnetic reluctance between the perpendicular and perpendicular axes created by the composite magnetic barrier structure is the key to achieving a high salient pole ratio and high magnetic reluctance torque in this invention.

[0036] Of particular note is the obvious convergence of magnetic field lines at the connection point between the irregular circular end magnetic barrier 12 and the inner arc-shaped magnetic barrier 7. The density of the magnetic field lines increases and their direction changes significantly near this connection point, indicating that this connection point effectively converges and guides the magnetic field lines, precisely directing the permanent magnet flux to the d-axis magnetic circuit while restricting the passage of the q-axis flux. This phenomenon directly verifies the effectiveness of the connection design between the end magnetic barrier and the inner magnetic barrier, demonstrating the crucial role of this structure in optimizing the magnetic circuit distribution and improving reluctance torque. Figure 4 This is a magnetic flux density cloud diagram of the motor under rated load conditions according to the present invention. The magnetic flux density distribution in the diagram is represented by a chromatographic gradient. The magnetic flux density values ​​are relatively high in the stator teeth, tooth tips, and the magnetic bridge region of the rotor salient poles, but all are within the safe range below the saturation magnetic flux density of the silicon steel sheet, with no local oversaturation. The magnetic flux density near the permanent magnet receiving slot 9 and inside the arc-shaped magnetic barrier is lower, as expected. The uniform magnetic flux density distribution indicates a balanced magnetic circuit design and full material utilization, which is beneficial for reducing core losses and improving motor efficiency.

[0037] Figure 5This is a comparison graph of the output torque of the motor of this invention and a traditional permanent magnet assisted synchronous reluctance motor. The horizontal axis represents time, ranging from 0 to 20 milliseconds, and the vertical axis represents torque, in Newton-meters (Nm), with a scale from -200 to 150. The solid curve represents the output torque characteristics of the motor of this invention, while the dashed curve represents the output torque characteristics of the comparative traditional permanent magnet assisted synchronous reluctance motor. From the overall trend of the torque curves, the torque curve of the motor of this invention exhibits periodic fluctuations within the 0 to 20 millisecond time range, with an average value higher than the comparative curve, indicating an improvement in torque output capability. Simultaneously, the torque fluctuation amplitude of the motor of this invention is significantly smaller than that of the comparative curve, and the curve shape is smoother. Measured data shows that the torque ripple coefficient of the motor of this invention is lower than that of the comparative curve. Specifically observing the curve fluctuations: the torque curve of the motor of this invention completes multiple full cycles within the 0 to 20 millisecond range, with relatively smooth transitions between peaks and troughs in each cycle, resulting in a relatively symmetrical curve shape. In contrast, the torque curve of the traditional permanent magnet assisted synchronous reluctance motor exhibits a larger fluctuation amplitude, with a more pronounced difference between peaks and troughs. This improvement in torque output characteristics is mainly due to the optimization of the air gap magnetic field distribution by the composite magnetic barrier structure used in this invention, as well as the reasonable matching of permanent magnet torque and reluctance torque.

[0038] Figure 6 This is a waveform diagram of the radial component (Bt) of the air gap magnetic flux density of the motor under no-load conditions. The horizontal axis represents the mechanical distance along the circumference of the air gap, corresponding to electrical angles, with a range of 0.2 to 1.2 meters. The vertical axis represents the Bt value, with a range of -0.25 to 0.25. The waveform is represented by a red curve, exhibiting a quasi-sine shape, completing one full cycle within the range of 0.2 to 1.2 meters. The waveform smoothly transitions between peaks and troughs, with continuous overall fluctuations and no obvious distortion or local spikes. As can be seen from the figure, the air gap magnetic flux density waveform exhibits certain harmonic components based on the fundamental wave, but the harmonic content is relatively low, and the overall waveform symmetry is good. The sinusoidal nature of the air gap magnetic flux density waveform is directly related to the quality of the motor's torque output. The waveform characteristics presented by this invention help reduce torque ripple and are consistent with... Figure 5 The measured smooth torque output in the test corroborates each other.

[0039] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that comprises a list of elements are included.

[0041] For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on," "mounted on," "fixed to," or "set on" another element, it may be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0043] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A reverse salient pole permanent magnet assisted synchronous reluctance motor with composite magnetic barriers, comprising a stator, a rotor, and a shaft arranged sequentially from the outside to the inside, characterized in that: The stator has 54 stator slots evenly distributed circumferentially on its inner side, and double-layer short-pitch distributed windings are configured in the slots; the stator yoke has 54 through-hole first circular cooling channels evenly distributed circumferentially. The outer circumferential profile of the rotor is an anti-salient pole structure, with eight semi-circular salient poles protruding towards the rotor center. Each semi-circular anti-salient pole has a concentric inner arc-shaped magnetic barrier and an outer arc-shaped magnetic barrier facing the stator. The inner arc-shaped magnetic barrier is broken in the middle to form a fracture, while the outer arc-shaped magnetic barrier is a continuous structure. Along the rotor circumference, there is a rectangular permanent magnet receiving slot between each pair of adjacent semi-circular salient poles, totaling eight slots. Each permanent magnet receiving slot contains a hybrid permanent magnet, which is composed of at least one layer of neodymium iron boron permanent magnet and at least one layer of samarium cobalt permanent magnet stacked along the thickness direction. Each permanent magnet receiving slot has an irregular circular end magnetic barrier at each end along the width direction, and the irregular circular end magnetic barrier is connected to the fracture of the adjacent inner arc-shaped magnetic barrier. Inside the rotor, in the area between the inner arc-shaped magnetic barrier, the outer arc-shaped magnetic barrier, and the shaft, 54 second circular cooling channels are evenly distributed circumferentially.

2. The anti-salient pole permanent magnet assisted synchronous reluctance motor with composite magnetic barriers according to claim 1, characterized in that, The inner arc-shaped magnetic barrier has the same thickness as the outer arc-shaped magnetic barrier.

3. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, In the hybrid permanent magnet, the thickness of the neodymium iron boron permanent magnet layer is greater than the thickness of the samarium cobalt permanent magnet layer.

4. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The stator slot is a pear-shaped slot.

5. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The axes of the first circular cooling channel and the second circular cooling channel are both parallel to the axis of the rotating shaft.

6. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The double-layer short-pitch distributed winding is a three-phase symmetrical winding, and adopts a star connection method.

7. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The inner and outer arc-shaped magnetic barriers are either air magnetic barriers or filled with non-magnetic materials.

8. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The neodymium iron boron permanent magnet layer and the samarium cobalt permanent magnet layer are tightly bonded together by adhesive or mechanical fixation.

9. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The first circular cooling channel and the second circular cooling channel are used to introduce a cooling medium, which is air, oil or a mixture of water and ethylene glycol.

10. A composite magnetic barrier anti-salient pole permanent magnet assisted synchronous reluctance motor according to claim 1, characterized in that, The rotor has eight semi-circular salient poles that are evenly distributed circumferentially.

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