A window type variable leakage magnetic starting permanent magnet motor

Abstract

The application discloses a window type variable leakage magnetic starting permanent magnet motor, which comprises a stator, a rotor and a motor rotating shaft. The stator comprises a stator tooth and a stator yoke, and an armature winding is distributed and wound on the stator tooth. The motor rotor is divided into a plurality of pole pairs, and each pole pair comprises a permanent magnet and a window type magnetic grid. The permanent magnet has a double-layer structure in the radial direction, and comprises a narrow permanent magnet and a wide permanent magnet. The two permanent magnets have the same magnetization direction in the radial direction, and the adjacent permanent magnets have opposite magnetization directions in the tangential direction. The window type magnetic grid comprises a thin magnetic bridge and a wide magnetic bridge, has two reinforcing ribs and a q-axis magnetic bridge. The double-layer permanent magnet and the double-layer magnetic bridge are combined to make the narrow permanent magnet provide the main magnetic flux and the rare leakage magnetic flux, and the wide permanent magnet provide the main leakage magnetic flux and the main magnetic flux, so that the motor torque density and the variation range of the motor permanent magnet flux can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of starting / generating permanent magnet motor technology, and particularly relates to a window-type variable leakage flux starting permanent magnet motor. Background Technology

[0002] The complexity of traditional helicopter structures leads to increased system coupling and weight, impacting fuel efficiency and reliability. To address these issues, the concept of more-electric helicopters (MEH) has emerged, migrating the power system to an electric system to reduce maintenance costs and improve reliability and safety. However, MEH helicopters face challenges in designing integrated starter-generator power systems, such as motor suitability for high-temperature environments and space constraints. Therefore, researching high-power-density and high-efficiency helicopter starter-generators to meet the dual needs of aircraft is crucial. Permanent magnet synchronous motors (PMSMs) utilize permanent magnet materials with high coercivity and high energy product, offering advantages over traditional motors in terms of high power density, high reliability, simple structure, and strong overload capacity. In the aviation field, PMSMs demonstrate significant advantages due to their stringent requirements on size and weight.

[0003] This type of permanent magnet motor requires heavy-load starting due to the load it is carrying. After starting, it switches to generator operation, requiring higher operating efficiency, making variable leakage flux motors suitable for this condition. However, most current variable leakage flux motors have a single-layer structure, and the permanent magnet thickness cannot be too thick. This is because an excessively thick permanent magnet increases leakage flux, but makes it more difficult to change the magnetic flux with armature current. On the other hand, a smaller permanent magnet thickness results in insufficient space utilization of the motor, failing to achieve the required torque output capacity for its size. Summary of the Invention

[0004] The purpose of this invention is to provide a window-type variable leakage flux starting permanent magnet motor to solve the technical problems that current variable leakage flux motors are mostly single-layer structures, and the thickness of the permanent magnet cannot be too thick, which makes it difficult to change the magnetic flux of the armature current; while a smaller permanent magnet thickness will result in insufficient space utilization of the motor and failure to achieve the torque output capability required for the same size.

[0005] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0006] A window-type variable leakage flux starting permanent magnet motor includes a stator, a rotor, and a motor shaft. The stator, rotor, and motor shaft are arranged sequentially from the outside to the inside. The stator includes stator teeth and a stator yoke, and the armature winding adopts a distributed winding, wound on the stator teeth. The motor rotor has multiple pole pairs, each pole pair being identical. Each pole pair contains a permanent magnet and a window-type magnetic grid. The permanent magnet has a double-layer structure in the radial direction, having a narrow permanent magnet and a wide permanent magnet. The two permanent magnets (narrow and wide permanent magnets) are magnetized in the same direction in the radial direction, while adjacent permanent magnets in the tangential direction are magnetized in opposite directions. The window-shaped magnetic grid has a thin magnetic bridge and a wide magnetic bridge, two reinforcing ribs, and a q-axis magnetic bridge; each pole pair contains two window-shaped magnetic grids; the wide and thin magnetic bridges are arranged circumferentially, with the order of the magnetic bridges from the inside to the outside along the radial direction being the wide magnetic bridge and the thin magnetic bridge; the reinforcing rib and the q-axis magnetic bridge are arranged radially, with the order of the first reinforcing rib, the q-axis magnetic bridge, and the second reinforcing rib along the circumferential direction from left to right. Narrow and wide permanent magnets jointly provide the main magnetic flux; the narrow permanent magnet provides a small amount of leakage flux, and the wide permanent magnet provides the main leakage flux. The operating principle of this type of motor is that when the motor needs to operate under heavy load, the magnetic flux generated by the q-axis will force the leakage flux to become the main magnetic flux, thereby increasing the permanent magnet flux linkage and improving the motor's torque performance. When the motor operates under light load, the q-axis current is small, and some of the magnetic flux becomes leakage flux again, which can effectively improve the motor's operating efficiency.

[0007] Furthermore, the thin magnetic bridges in the window-type magnetic grid, due to their small thickness, are prone to saturation, which can prevent excessive magnetic leakage from narrow permanent magnets. Conversely, the large thickness of the wide magnetic bridges can effectively increase the magnetic leakage of wide permanent magnets, thereby effectively increasing the variable magnetic leakage flux.

[0008] Furthermore, by combining double-layer permanent magnets and double-layer magnetic bridges, the narrow permanent magnet can provide the main magnetic flux and the sparse leakage magnetic flux, while the wide permanent magnet provides the main leakage magnetic flux and the main main magnetic flux. Therefore, this combination can effectively improve the motor torque density and the range of variation of the motor permanent magnet flux linkage.

[0009] Furthermore, the addition of reinforcing ribs can effectively improve the mechanical strength of the rotor.

[0010] Furthermore, the q-axis magnetic bridge configuration can reduce the q-axis magnetic reluctance and increase the sensitivity of leakage flux to armature current.

[0011] The window-type variable leakage flux starting permanent magnet motor of the present invention has the following advantages:

[0012] 1. The stator of this invention is the same as that of a traditional permanent magnet motor, but the rotor is significantly different. This patented invention innovatively constructs the main magnetic flux (provided jointly by narrow and wide permanent magnets) and leakage flux (with a small amount of leakage flux provided by the narrow permanent magnet and the main leakage flux provided by the wide permanent magnet) by integrating a double-layer permanent magnet and a double-layer magnetic barrier design. Compared to traditional variable leakage flux permanent magnet motors, the double-layer permanent magnet design can effectively increase the main magnetic flux, thereby increasing the motor torque density; it can also increase the leakage flux, effectively improving the variation range of the motor's permanent magnet flux linkage.

[0013] 2. The design of the q-axis magnetic bridge in this invention can effectively reduce the q-axis magnetic reluctance, thereby reducing the armature current and increasing the sensitivity of leakage flux to the armature current; at the same time, the design of the reinforcing rib can effectively improve the rotor strength, thus making it more suitable for medium and high speed applications. Attached Figure Description

[0014] Figure 1 This is a cross-sectional structural diagram of the motor according to the present invention.

[0015] Figure 2 This is a cross-sectional structural diagram of the motor of the present invention, and a magnetic field diagram under no-load conditions.

[0016] Figure 3 This shows the variation of permanent magnet flux linkage under different q-axis currents in the motor of the present invention.

[0017] The markings in the diagram are as follows: 1. Stator; 1.1. Stator teeth; 1.2. Stator yoke; 2. Rotor; 2.1. Fine magnetic bridge; 2.2. Fine magnetic bridge; 2.3. Reinforcing rib; 2.4. Wide magnetic bridge; 3. Permanent magnet; 3.1. Narrow permanent magnet; 3.2. Wide permanent magnet; 4. Motor rotor; 5. Armature winding; 6. Motor shaft. Detailed Implementation

[0018] To better understand the purpose, structure, and function of this invention, a window-type variable leakage flux initiating permanent magnet motor of this invention will be described in further detail below with reference to the accompanying drawings.

[0019] A window-type variable leakage flux starting permanent magnet motor includes a stator 1, a rotor 4, and a motor shaft 6. The stator 1, rotor 2, and motor shaft 6 are arranged sequentially from the outside to the inside. The stator 1 includes stator teeth 1.1 and a stator yoke 1.2, and the armature winding 5 is a distributed winding wound on the stator teeth 1.1. The motor rotor 4 has multiple pole pairs, of which one pole pair (P1) is shown in the figure, and each pole pair is identical. Underneath a pole pair are permanent magnets 3 and window-type magnetic grids 2. The permanent magnets 3 have a double-layer structure in the radial direction, with a narrow permanent magnet 3.1 and a wide permanent magnet 3.2. The two permanent magnets (narrow permanent magnet 3.1 and wide permanent magnet 3.2) are magnetized in the same direction in the radial direction, while adjacent permanent magnets in the tangential direction are magnetized in opposite directions. The window-shaped magnetic grid 2 has a thin magnetic bridge 2.2 and a wide magnetic bridge 2.4, two reinforcing ribs 2.3, and a q-axis magnetic bridge 2.1; each pole pair has two window-shaped magnetic grids 2; the wide magnetic bridge 2.4 and the thin magnetic bridge 2.2 are arranged circumferentially, and the magnetic bridge sequence from the inside to the outside along the radial direction is wide magnetic bridge 2.4 and thin magnetic bridge 2.2; the reinforcing rib 2.3 and the q-axis magnetic bridge 2.1 are arranged radially, and the sequence from left to right along the circumferential direction is first reinforcing rib, q-axis magnetic bridge 2.1, and second reinforcing rib. Narrow permanent magnets 3.1 and wide permanent magnets 3.2 jointly provide the main magnetic flux; narrow permanent magnets 3.1 provide a small amount of leakage flux, and wide permanent magnets 3.2 provide the main leakage flux. The operating principle of this type of motor is that when the motor needs to operate under heavy load, the magnetic flux generated by the q-axis will force the leakage flux to become the main magnetic flux, thereby increasing the permanent magnet flux linkage of the motor and improving the motor torque performance. When the motor is running under light load, the q-axis current is small, and some of the magnetic flux becomes leakage flux, which can effectively improve the motor's operating efficiency.

[0020] The thin magnetic bridge 2.1 in the window-type magnetic grid 2 is prone to saturation due to its small thickness, which can prevent excessive magnetic leakage from the narrow permanent magnet 3.1. On the other hand, the wide magnetic bridge with a large thickness can effectively increase the magnetic leakage of the wide permanent magnet 3.2, and can effectively increase the variable magnetic leakage flux.

[0021] The combined arrangement of double-layer permanent magnets and double-layer magnetic bridges allows the narrow permanent magnet 3.1 to provide the main magnetic flux and a small amount of leakage flux, while the wide permanent magnet 3.2 provides the main leakage flux and the main magnetic flux. Therefore, this combined arrangement can effectively improve the motor torque density and the range of variation of the motor permanent magnet flux linkage.

[0022] The addition of the reinforcing rib 2.3 can effectively improve the mechanical strength of the rotor.

[0023] The q-axis magnetic bridge 2.1 described above can reduce the q-axis magnetic reluctance and improve the sensitivity of leakage flux to armature current.

[0024] The stator of this invention is the same as that of a traditional permanent magnet motor, but the rotor is significantly different. This patented invention innovatively constructs the main magnetic flux (provided jointly by narrow and wide permanent magnets) and leakage flux (with a small amount of leakage flux provided by the narrow permanent magnet and the main leakage flux provided by the wide permanent magnet) by integrating a double-layer permanent magnet and a double-layer magnetic barrier design. Compared to traditional variable leakage flux permanent magnet motors, the double-layer permanent magnet design effectively increases the main magnetic flux, thereby increasing the motor's torque density; it also increases the leakage flux, effectively expanding the range of variation of the motor's permanent magnet flux linkage.

[0025] The design of the q-axis magnetic bridge of the present invention can effectively reduce the q-axis magnetic reluctance, thereby reducing the armature current and increasing the sensitivity of leakage flux to armature current; at the same time, the design of the reinforcing rib can effectively improve the rotor strength, thus making it more suitable for medium and high speed applications.

[0026] The operating principle of a window-type variable leakage flux-initiated permanent magnet motor disclosed in this invention is as follows:

[0027] When the motor is under heavy load, the magnetic flux generated by the q-axis forces the leakage flux to become the dominant flux, increasing the permanent magnet flux linkage and thus improving the motor's torque performance. Conversely, when the motor is under light load, the q-axis current is smaller, and some of the magnetic flux becomes leakage flux again, effectively improving the motor's operating efficiency.

[0028] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A window-type variable leakage flux starting permanent magnet motor, characterized in that, It includes a stator (1), a rotor (4), and a motor shaft (6); The stator (1), rotor (4) and motor shaft (6) are arranged in a spatial order from the outside to the inside; The stator (1) includes stator teeth (1.1) and stator yoke (1.2), and the armature winding (5) adopts distributed winding and is wound on the stator teeth (1.1); The motor rotor (4) has multiple pole pairs, each pole pair being identical; each pole pair contains a permanent magnet (3) and a window-shaped magnetic grid (2); the permanent magnet (3) has a double-layer structure in the radial direction, having a narrow permanent magnet (3.1) and a wide permanent magnet (3.2), the narrow permanent magnet (3.1) and the wide permanent magnet (3.2) in the radial direction are magnetized in the same direction, and adjacent permanent magnets in the tangential direction are magnetized in opposite directions; the window-shaped magnetic grid (2) has a thin magnetic bridge (2.2) and a wide magnetic bridge (2.2). The bridge (2.4) has two reinforcing ribs (2.3) and a q-axis magnetic bridge (2.1); each pole pair has two window-shaped magnetic grids (2); the wide magnetic bridge (2.4) and the thin magnetic bridge (2.2) are arranged circumferentially, and the magnetic bridges are arranged radially from the inside to the outside in the order of wide magnetic bridge (2.4) and thin magnetic bridge (2.2); the reinforcing rib (2.3) and the q-axis magnetic bridge (2.1) are arranged radially, and the reinforcing rib is arranged radially from left to right in the order of first reinforcing rib, q-axis magnetic bridge (2.1), and second reinforcing rib; Narrow permanent magnets (3.1) and wide permanent magnets (3.2) jointly provide the main magnetic flux; narrow permanent magnets (3.1) provide a small amount of leakage flux and wide permanent magnets (3.2) provide the main leakage flux; When the motor needs to run under heavy load, the magnetic flux generated by the q-axis will force the leakage flux to become the main flux, thereby increasing the permanent magnet flux linkage of the motor; while when the motor runs under light load, the q-axis current is small, and part of the magnetic flux becomes leakage flux again.

2. The window-type variable leakage flux starting permanent magnet motor according to claim 1, characterized in that, In the window-type magnetic grid (2), the thin magnetic bridge (2.2) has a small thickness, while the wide magnetic bridge (2.4) has a large thickness.

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