Small-sized high-power local area power supply permanent magnet synchronous generator

Abstract

This invention relates to the field of permanent magnet synchronous power generation technology, and more particularly to a small, high-power, locally powered permanent magnet synchronous generator. The generator includes a stator assembly, a rotor assembly, a frame, and end cover assemblies. The invention achieves a continuous and smooth electromagnetic energy conversion path and ensures uniform magnetic field distribution through the coaxial arrangement of the stator and rotor assemblies. The slot walls of the rotor magnets near the radial air gap adopt an asymmetric profile based on electromagnetic field optimization. Adjusting the profile shape improves the air gap magnetic flux density waveform, reduces harmonic components and electromagnetic noise, and increases electromagnetic energy conversion efficiency. The frame surrounds the stator and is equipped with cooling channels around the stator, ensuring uniform heat dissipation during operation, improving temperature rise control capabilities, and achieving efficient energy utilization. This effectively solves the problems of low energy conversion efficiency and unstable operation caused by uneven air gap magnetic flux density and insufficient heat dissipation, thereby contributing to energy conservation and emission reduction.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous power generation technology, and in particular to a small, high-power, locally powered permanent magnet synchronous generator. Background Technology

[0002] With the continued growth in the utilization of clean energy and the demand for high-efficiency power supplies, miniature high-power permanent magnet synchronous generators have shown broad application prospects in achieving local power supply, energy conservation and emission reduction, and low-noise, pollution-free operation. Especially in urban communities, factories, micro power stations, and distributed energy systems, higher demands are placed on the miniaturization, high power density, continuous and reliable power supply, and thermal management capabilities of the generators. However, ensuring stable output power, optimizing electromagnetic performance, suppressing electromagnetic noise, and effectively controlling temperature rise within limited space remain core challenges that miniature high-power power supply technology urgently needs to overcome.

[0003] Chinese Patent Application Publication No. CN1143850A discloses a novel permanent magnet synchronous generator. The generator consists of a stationary stator, stator coils, a rotor, and a housing. The rotor is made into an axial fan-shaped cylinder by rare earth magnetic poles, a rotor core, and a rotating shaft. The main winding coils are embedded in 70-80% of the slots of the stator, and low-voltage sensing coils and high-voltage charging coils for the power unit ignition system are wound in the empty slots.

[0004] It is evident that the conventional generators that have been disclosed have the following problems: their rotor structure adopts an axial flow fan-shaped cylinder, the magnetic circuit design is complex, and the air gap magnetic flux density distribution is not uniform enough, resulting in low electromagnetic energy conversion efficiency; their stator slot wiring is insufficient to fully utilize magnetic energy, and additional wiring is required in the empty slots, increasing structural complexity and manufacturing difficulty; their harmonic suppression measures between the rotor and stator are limited, which easily generates cogging torque fluctuations and electromagnetic noise; their heat dissipation capacity is insufficient, making it difficult to meet the temperature rise control requirements for continuous high-power operation; and their large size makes it difficult to achieve compact layout in community or micro local power supply scenarios. Summary of the Invention

[0005] To address this, the present invention provides a small, high-power, locally powered permanent magnet synchronous generator, which overcomes the problems of low energy conversion efficiency and unstable operation caused by uneven air gap magnetic flux density and insufficient heat dissipation in the prior art through rotor asymmetric profile optimization and spiral water cooling channels.

[0006] To achieve the above objectives, the present invention provides a small, high-power, locally powered permanent magnet synchronous generator, comprising: The stator assembly and rotor assembly are coaxially arranged; The stator assembly includes a stator core, and the inner circumference of the stator core is provided with a plurality of axially extending stator slots; The rotor assembly includes a rotor core and a permanent magnet. The rotor core has several magnetic steel slots on its circumference for accommodating the permanent magnet. The rotor assembly is rotatably supported within the stator assembly via a rotating shaft; A radial air gap is provided between the stator assembly and the rotor assembly; The profile of the magnetic steel groove near the radial air gap side is an asymmetric profile determined based on the electromagnetic field. The frame covers the outer periphery of the stator assembly, and has cooling channels surrounding the stator assembly inside; End cap assemblies are installed at both ends of the base to support the rotating shaft; The stator slot, the magnet slot, and the radial air gap together form an electromagnetic energy conversion path.

[0007] Furthermore, the asymmetric profile is configured to suppress first and second specific low-order spatial magnetic flux density harmonics.

[0008] Furthermore, the profile of the magnetic groove wall near the radial air gap side is defined by a polar coordinate function. ρ(θ)=R+A×cos(N×θ)+B×cos(M×θ); Wherein, ρ is the radial distance from a point on the contour line of the slot wall to the rotor center of the rotor assembly; θ is the angle of the point relative to the rotor magnetic pole center line of the rotor assembly; R is the preset reference radius; A is the preset first amplitude coefficient; B is the preset second amplitude coefficient; N is the preset first harmonic order; and M is the preset second harmonic order.

[0009] Furthermore, the preset first harmonic order corresponds to the first specific lower order, and the preset second harmonic order corresponds to the second specific lower order.

[0010] Furthermore, the radial distance of the point on the center line of the rotor magnetic pole is greater than the radial distance of the point on the bisecting angle line of two adjacent center lines of the rotor magnetic pole.

[0011] Furthermore, the cooling channel is a spiral water-cooled channel surrounding the stator assembly.

[0012] Furthermore, the stator slot is a semi-closed trapezoidal slot.

[0013] Furthermore, the rated power of the small, high-power local power permanent magnet synchronous generator is pre-matched with the heat dissipation capacity of the cooling channel.

[0014] Furthermore, the electromagnetic properties of the asymmetric profile are pre-matched with the pole-slot mating parameters of the stator slot.

[0015] Furthermore, the permanent magnet is made of high-performance permanent magnet material and has a corrosion-resistant coating on its surface.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the coaxial arrangement of the stator assembly and the rotor assembly ensures a continuous and smooth electromagnetic energy conversion path and uniform magnetic field distribution; the slot wall of the rotor magnet slot near the radial air gap side adopts an asymmetric profile based on electromagnetic field optimization, which improves the air gap magnetic flux density waveform, reduces harmonic components and electromagnetic noise, and improves electromagnetic energy conversion efficiency by adjusting the profile shape; the stator is covered by the outer periphery of the frame and a cooling channel is set around the stator to uniformly dissipate the heat generated during operation and improve the temperature rise control capability; the end cover assembly is installed at both ends of the frame to provide reliable support for the rotating shaft and ensure stable rotor rotation. The whole structure achieves compact structure, sufficient heat dissipation, reasonable magnetic field distribution and high-efficiency energy output, meeting the dual requirements of miniaturization and high-power power supply.

[0017] Furthermore, by designing the slot wall of the rotor magnet near the air gap side as an asymmetrical profile, the air gap magnetic flux distribution can be effectively adjusted, thereby suppressing the first and second specific low-order spatial magnetic flux density harmonics, reducing cogging torque and magnetic flux density distortion, and improving the electromagnetic waveform quality. The amplitude coefficient and harmonic order of the asymmetrical profile are matched with the rotor pole number and stator slot geometric parameters, achieving electromagnetic performance optimization while maintaining the continuity and stability of the energy conversion path, thus improving the generator's output efficiency and operational stability.

[0018] Furthermore, the groove wall profile of the magnetic steel groove near the radial air gap side is precisely defined by a polar coordinate function, so that the radial distance of the rotor groove wall changes with the angle to form a controllable asymmetric shape. Among them, the reference radius determines the overall air gap distance, and the first amplitude coefficient and the second amplitude coefficient control the intensity of specific harmonic components. The first harmonic order and the second harmonic order correspond to the first specific low-order and the second specific low-order spatial magnetic flux density harmonics. The joint adjustment can form an optimized magnetic flux density distribution in the magnetic pole centerline and the inter-pole region. Through this profile design, the air gap magnetic flux is smoothly distributed in space, and specific low-order harmonics are suppressed, thereby reducing cogging torque fluctuation and magnetic flux density distortion, improving the output voltage waveform quality and electromagnetic energy conversion efficiency, while maintaining the continuity of inter-pole magnetic flux and energy transfer stability, so as to achieve efficient and stable operation of the generator.

[0019] Furthermore, by precisely matching the preset harmonic order with the specific low-order spatial magnetic flux density harmonics to be suppressed, the precise optimization of the motor's magnetic field waveform is achieved, effectively weakening the main harmonic components that cause torque pulsation and electromagnetic noise, thereby significantly improving the generator's operational stability, efficiency, and reliability.

[0020] Furthermore, by minimizing the air gap at the center of the magnetic pole and maximizing the air gap between the poles, a non-uniform air gap magnetic field is formed, which effectively optimizes the air gap magnetic flux density waveform, making it closer to a sinusoidal distribution. This significantly reduces torque pulsation and electromagnetic noise, while increasing the fundamental amplitude of the air gap magnetic field. Ultimately, this achieves a comprehensive optimization effect of reducing motor vibration noise, improving operational stability, and enhancing torque output capability.

[0021] Furthermore, by designing the cooling channel as a spiral water-cooling channel surrounding the stator assembly, the coolant can fully cover the outer periphery of the stator and form a longer heat exchange path during the flow process, significantly improving heat dissipation efficiency; the heat generated by the stator operation can be discharged in a timely and uniform manner, and the temperature rise is effectively controlled within a safe range, avoiding insulation aging and performance degradation, thereby ensuring the continuous and stable operation of the generator under high power density conditions.

[0022] Furthermore, by designing the stator slots as semi-closed trapezoidal slots, the slot opening is moderate and the tooth shoulder strength is enhanced, which not only improves the mechanical strength of the stator teeth, but also reduces leakage flux and cogging torque; at the same time, it improves the winding embedding and fixing conditions, increases the slot fill factor and heat dissipation performance, thereby improving the electromagnetic energy conversion efficiency and ensuring the stability and reliability of generator operation.

[0023] Furthermore, by pre-matching the generator's rated power with the cooling channel's heat dissipation capacity, it is ensured that the heat generated during high power output can be effectively carried away by the cooling system, preventing the motor from overheating. This ensures that the motor can operate stably and continuously at its rated power, while significantly improving the motor's overload capacity and operational reliability.

[0024] Furthermore, by pre-matching the electromagnetic properties of the asymmetric profile with the pole-slot matching parameters of the stator slots, the air gap magnetic flux density distribution and the pole-slot matching relationship are optimized in synergy, avoiding magnetic flux density distortion and torque pulsation caused by harmonic superposition; at the same time, it ensures the balanced transfer of electromagnetic energy between the stator and rotor, improves the electromagnetic energy conversion efficiency and output waveform quality, thereby achieving stable, low-noise, and high-efficiency operation of the generator.

[0025] Furthermore, by employing high-performance permanent magnet materials and applying a corrosion-resistant coating to their surface, the rotor possesses high remanence and high coercivity, thereby increasing the air gap magnetic flux density and output power density. At the same time, the corrosion-resistant coating effectively prevents the permanent magnets from demagnetizing and failing in humid or salt spray environments, thus ensuring the long-term stable operation of the generator and its durable and reliable electromagnetic performance. Attached Figure Description

[0026] Figure 1 This is a front cross-sectional view of the small, high-power, locally powered permanent magnet synchronous generator in this embodiment. Figure 2 This is a left cross-sectional view of the small, high-power, locally powered permanent magnet synchronous generator in this embodiment. Figure 3 This is a left sectional view of the stator assembly in this embodiment; Figure 4 This is a left-side cross-sectional view of the rotor assembly in this embodiment. Detailed Implementation

[0027] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] Please see Figure 1 and Figure 2 As shown, Figure 1 This is a front cross-sectional view of the small, high-power, locally powered permanent magnet synchronous generator in this embodiment. Figure 2 This is a left cross-sectional view of a small, high-power, locally powered permanent magnet synchronous generator according to this embodiment. This embodiment provides a small, high-power, locally powered permanent magnet synchronous generator, comprising: Stator assembly 1 and rotor assembly 2 are coaxially arranged; The stator assembly 1 includes a stator core 11, and the inner circumference of the stator core 11 is provided with a plurality of axially extending stator slots 12; The rotor assembly 2 includes a rotor core 21 and a permanent magnet 22. The rotor core is provided with a plurality of magnetic steel slots 23 for accommodating the permanent magnet 22. The rotor assembly 2 is rotatably supported within the stator assembly 1 via a rotating shaft 3; A radial air gap is provided between the stator assembly 1 and the rotor assembly 2; The profile of the magnetic steel groove 23 near the radial air gap side is an asymmetric profile determined based on the electromagnetic field. The base 4 covers the outer periphery of the stator assembly 1, and has a cooling channel 41 surrounding the stator assembly 1 inside; End cap assembly 5 is installed at both ends of the base 4 to support the rotating shaft 3; The stator slot 12, the magnet slot 23, and the radial air gap together form an electromagnetic energy conversion path.

[0030] The coaxial arrangement of the stator and rotor assemblies ensures a continuous and smooth electromagnetic energy conversion path, guaranteeing a uniform magnetic field distribution. The rotor magnet slots near the radial air gap adopt an asymmetric profile based on electromagnetic field optimization. By adjusting the profile shape, the air gap magnetic flux density waveform is improved, harmonic components and electromagnetic noise are reduced, and the electromagnetic energy conversion efficiency is increased. The stator is covered by the outer periphery of the frame and a cooling channel is set around the stator to uniformly dissipate the heat generated during operation and improve temperature rise control capability. The end cover assembly is installed at both ends of the frame to provide reliable support for the shaft, ensuring stable rotor rotation. The overall design achieves a compact structure, sufficient heat dissipation, reasonable magnetic field distribution, and efficient energy output, meeting the dual requirements of miniaturization and high-power power supply.

[0031] Specifically, the asymmetric profile is configured to suppress first and second specific low-order spatial magnetic flux density harmonics.

[0032] The first and second specific low-order harmonics refer to the spatial harmonic orders in the air gap magnetic flux density distribution of the generator, that is, the number of repetitions of the magnetic flux density distribution along the circumference. They correspond to the low-order harmonic components in the air gap magnetic field that easily cause cogging torque fluctuations and output waveform distortion. By optimizing the asymmetric profile of the magnet slots, these two low-order harmonics can be suppressed, thereby improving the electromagnetic performance and operational stability of the generator. The first specific low-order harmonic depends on the matching relationship between the number of stator slots and the number of rotor poles, and is usually set between the 3rd and 7th orders. In this embodiment, it is set to the 5th order, which can effectively suppress the corresponding cogging torque and magnetic flux density waveform distortion. The second specific low-order harmonic depends on the matching relationship between the number of stator slots and the number of rotor poles, and is usually set between the 5th and 9th orders. In this embodiment, it is set to the 7th order, which can further reduce electromagnetic vibration and noise caused by higher-order harmonics.

[0033] By designing the slot wall of the rotor magnet slot near the air gap side as an asymmetrical profile, the air gap magnetic flux distribution can be effectively adjusted, suppressing the first and second specific low-order spatial magnetic flux density harmonics, thereby reducing cogging torque and magnetic flux density distortion, and improving the quality of electromagnetic waveforms. The amplitude coefficient and harmonic order of the asymmetrical profile are matched with the rotor pole number and stator slot geometric parameters, achieving electromagnetic performance optimization while maintaining the continuity and stability of the energy conversion path, thus improving the generator's output efficiency and operational stability.

[0034] Please see Figure 3 As shown, this is a left-side cross-sectional view of the stator assembly in this embodiment. In this embodiment, the contour of the magnet slot 23 near the radial air gap side is defined by a polar coordinate function. ρ(θ)=R+A×cos(N×θ)+B×cos(M×θ); Wherein, ρ is the radial distance from a point on the contour line of the slot wall to the rotor center of the rotor assembly; θ is the angle of the point relative to the rotor magnetic pole center line of the rotor assembly; R is the preset reference radius; A is the preset first amplitude coefficient; B is the preset second amplitude coefficient; N is the preset first harmonic order; and M is the preset second harmonic order.

[0035] The preset reference radius is the radial design reference of the profile line. Its value mainly depends on the basic dimensions of the rotor core and the air gap length requirements, and is usually set between 95% and 98% of the rotor outer diameter. In this embodiment, it is set to 96.5% of the rotor outer diameter, which can ensure that the magnetic circuit reluctance is minimized while avoiding mechanical interference. The preset first amplitude coefficient is used to control the 5th harmonic suppression intensity. Its value depends on the target harmonic content and the amount of permanent magnets used, and is usually set between 0.5mm and 2mm. In this embodiment, it is set to 1.2mm, which can effectively weaken the 5th spatial magnetic flux density harmonic. The preset second amplitude coefficient is used to adjust the degree of 7th harmonic suppression. Its value depends on the 7th harmonic amplitude and heat dissipation requirements, and is usually set between 0.5mm and 2mm. In this embodiment, it is set to 0.8mm, which can accurately suppress the 7th harmonic while avoiding local overheating. The preset first harmonic order corresponds to the main harmonic order that needs to be suppressed. Its value depends on the tooth harmonic order generated by the motor pole slot matching, and is usually the 5th or 7th order. In this embodiment, the order is set to 5, which can optimize the most important harmonic source; the preset second harmonic order corresponds to the number of minor harmonics that need to be suppressed, and its value also depends on the pole-slot matching characteristics. It is usually 5 or 7. In this embodiment, it is set to 7, which can work with the preset first harmonic order to achieve wide-spectrum harmonic suppression.

[0036] The profile of the slot wall near the radial air gap side of the magnet slot is precisely defined by a polar coordinate function, so that the radial distance of the rotor slot wall changes with the angle to form a controllable asymmetric shape. Among them, the reference radius determines the overall air gap distance, and the first amplitude coefficient and the second amplitude coefficient control the intensity of specific harmonic components. The first harmonic order and the second harmonic order correspond to the first specific low-order and the second specific low-order spatial magnetic flux density harmonics. The joint adjustment can form an optimized magnetic flux density distribution in the magnetic pole centerline and the inter-pole region. Through this profile design, the air gap magnetic flux is smoothly distributed in space, and specific low-order harmonics are suppressed, thereby reducing cogging torque fluctuation and magnetic flux density distortion, improving the output voltage waveform quality and electromagnetic energy conversion efficiency, while maintaining the continuity of inter-pole magnetic flux and energy transfer stability, so as to achieve efficient and stable operation of the generator.

[0037] Specifically, the preset first harmonic order corresponds to the first specific lower order, and the preset second harmonic order corresponds to the second specific lower order.

[0038] By precisely matching the preset harmonic order with the specific low-order spatial magnetic flux density harmonics to be suppressed, the waveform of the motor's magnetic field is precisely optimized, effectively reducing the main harmonic components that cause torque pulsation and electromagnetic noise, thereby significantly improving the generator's operational stability, efficiency, and reliability.

[0039] Specifically, the radial distance of the point on the center line of the rotor magnetic pole is greater than the radial distance of the point on the bisecting angle line of two adjacent center lines of the rotor magnetic pole.

[0040] By minimizing the air gap at the center of the magnetic pole and maximizing the air gap between the poles, a non-uniform air gap magnetic field is formed, effectively optimizing the air gap magnetic flux density waveform to make it closer to a sinusoidal distribution. This significantly reduces torque pulsation and electromagnetic noise, while also increasing the fundamental amplitude of the air gap magnetic field. Ultimately, this achieves a comprehensive optimization effect of reducing motor vibration and noise, improving operational stability, and enhancing torque output capability.

[0041] Specifically, the cooling channel 41 is a spiral water-cooling channel surrounding the stator assembly 1.

[0042] By designing the cooling channel as a spiral water-cooling channel surrounding the stator assembly, the coolant can fully cover the outer periphery of the stator and form a longer heat exchange path during the flow process, significantly improving heat dissipation efficiency; the heat generated by the stator operation can be discharged in a timely and uniform manner, and the temperature rise is effectively controlled within a safe range, avoiding insulation aging and performance degradation, thereby ensuring the continuous and stable operation of the generator under high power density conditions.

[0043] Please see Figure 4 As shown, it is a left-side cross-sectional view of the rotor assembly in this embodiment. In this embodiment, the stator slot 12 is a semi-closed trapezoidal slot.

[0044] By designing the stator slots as semi-closed trapezoidal slots, the slot opening is moderate and the tooth shoulder strength is enhanced, which not only improves the mechanical strength of the stator teeth, but also reduces leakage flux and cogging torque. At the same time, it improves the winding embedding and fixing conditions, increases the slot fill factor and heat dissipation performance, thereby improving the electromagnetic energy conversion efficiency and ensuring the stability and reliability of generator operation.

[0045] Specifically, the rated power of the small, high-power local power permanent magnet synchronous generator is pre-matched with the heat dissipation capacity of the cooling channel 41.

[0046] By pre-matching the generator's rated power with the cooling channel's heat dissipation capacity, it is ensured that the heat generated during high power output can be effectively carried away by the cooling system, preventing the motor from overheating. This ensures that the motor can operate stably and continuously at its rated power, while significantly improving the motor's overload capacity and operational reliability.

[0047] Specifically, the electromagnetic properties of the asymmetric profile are pre-matched with the pole slot matching parameters of the stator slot.

[0048] By pre-matching the electromagnetic properties of the asymmetric profile with the pole-slot matching parameters of the stator slots, the air gap magnetic flux density distribution and the pole-slot matching relationship are optimized in synergy, avoiding magnetic flux density distortion and torque pulsation caused by harmonic superposition; at the same time, it ensures the balanced transfer of electromagnetic energy between the stator and rotor, improves the electromagnetic energy conversion efficiency and output waveform quality, thereby achieving stable, low-noise, and high-efficiency operation of the generator.

[0049] Specifically, the permanent magnet 22 is made of high-performance permanent magnet material and has a corrosion-resistant coating on its surface.

[0050] By using high-performance permanent magnet materials and applying a corrosion-resistant coating to their surface, the rotor has high remanence and high coercivity, which improves the air gap magnetic flux density and output power density. At the same time, the corrosion-resistant coating effectively prevents the permanent magnets from demagnetizing and failing in humid or salt spray environments, thereby ensuring the long-term stable operation of the generator and its durable and reliable electromagnetic performance.

[0051] Based on the above-described specific structure and performance optimization, this embodiment can also design various small, high-power local power supply permanent magnet synchronous generators according to different power levels. Specific embodiments are as follows: Example 1

[0052] This embodiment is a three-phase permanent magnet synchronous motor with a rated power of 1000kW, a rated voltage of 380V AC, a rated current of 1730A AC, a rated torque of 5820Nm, a rated power factor of 0.9, a rated efficiency of 95.5%, a synchronous speed of 1500rpm, and a synchronous frequency of 50Hz. The winding insulation class is C (temperature index 220°C), the cooling method is water jacket cooling of the frame, it is horizontally mounted, the winding connection is delta, and the bearings are SKF bearings (6222 for the drive end and NU222ECP ML for the non-drive end). The motor weighs approximately 1280kg. This embodiment, while ensuring high power output, achieves efficient electromagnetic energy conversion and stable operation through the above-mentioned stator and rotor structure optimization, asymmetrical contour design, and spiral water cooling channel. Example 2

[0053] This embodiment is a three-phase permanent magnet synchronous motor with a rated power of 500kW, a rated voltage of 380V AC, a rated current of 810A AC, a rated torque of 3185Nm, a rated power factor of 0.9, a rated efficiency of 95.3%, a synchronous speed of 1500rpm, and a synchronous frequency of 50Hz. The winding insulation class is C (temperature index 220°C), the cooling method is water jacket cooling of the frame, it is horizontally mounted, the winding connection is delta, and the bearings are SKF bearings (6222 on the drive end and NU222ECP ML on the non-drive end). The motor weighs approximately 1000kg. This embodiment, under medium power requirements, achieves a balance between size, weight, and heat dissipation performance through the same structural optimization and heat dissipation design, ensuring stable and efficient generator operation.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A small, high-power, locally powered permanent magnet synchronous generator, characterized in that, include: The stator assembly and rotor assembly are coaxially arranged; The stator assembly includes a stator core, and the inner circumference of the stator core is provided with a plurality of axially extending stator slots; The rotor assembly includes a rotor core and a permanent magnet. The rotor core has several magnetic steel slots on its circumference for accommodating the permanent magnet. The rotor assembly is rotatably supported within the stator assembly via a rotating shaft; A radial air gap is provided between the stator assembly and the rotor assembly; The profile of the magnetic steel groove near the radial air gap side is an asymmetric profile determined based on the electromagnetic field. The frame covers the outer periphery of the stator assembly, and has cooling channels surrounding the stator assembly inside; End cap assemblies are installed at both ends of the base to support the rotating shaft; The stator slot, the magnet slot, and the radial air gap together form an electromagnetic energy conversion path. The asymmetric profile is configured to suppress first and second specific low-order spatial magnetic flux density harmonics. The profile of the magnetic steel groove wall near the radial air gap side is defined by a polar coordinate function. ρ(θ)=R+A×cos(N×θ)+B×cos(M×θ); Wherein, ρ is the radial distance from a point on the contour line of the slot wall to the rotor center of the rotor assembly; θ is the angle of the point relative to the rotor magnetic pole center line of the rotor assembly; R is the preset reference radius; A is the preset first amplitude coefficient; B is the preset second amplitude coefficient; N is the preset first harmonic order; M is the preset second harmonic order; The cooling channel is a spiral water-cooled channel surrounding the stator assembly; The electromagnetic properties of the asymmetric profile are pre-matched with the pole slot matching parameters of the stator slot.

2. The small, high-power, locally powered permanent magnet synchronous generator according to claim 1, characterized in that, The preset first harmonic order corresponds to the first specific lower order, and the preset second harmonic order corresponds to the second specific lower order.

3. The small, high-power, locally powered permanent magnet synchronous generator according to claim 2, characterized in that, The radial distance of the point on the center line of the rotor magnetic pole is greater than the radial distance of the point on the bisecting angle line of two adjacent center lines of the rotor magnetic pole.

4. The small, high-power, locally powered permanent magnet synchronous generator according to claim 3, characterized in that, The stator slot is a semi-closed trapezoidal slot.

5. The small, high-power, locally powered permanent magnet synchronous generator according to claim 4, characterized in that, The rated power of the small, high-power local power permanent magnet synchronous generator is pre-matched with the heat dissipation capacity of the cooling channel.

6. The small, high-power, locally powered permanent magnet synchronous generator according to claim 5, characterized in that, The permanent magnet is made of high-performance permanent magnet material and has a corrosion-resistant coating on its surface.

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