MW-level full-superconducting synchronous motor based on stepped superconducting coils

Abstract

The invention provides an MW-level full-superconducting synchronous motor based on stepped superconducting coils, which relates to the field of motors and comprises a stator superconducting winding, a rotor superconducting winding, a stator low-temperature sealing system, a rotor dynamic low-temperature sealing system and a vacuum sealing system. The stator superconducting winding provides a low-temperature operation environment through the stator low-temperature sealing system, the rotor superconducting winding provides a low-temperature operation environment through the rotor dynamic low-temperature sealing system, and the vacuum sealing system of the motor provides a vacuum environment for the rotor dynamic low-temperature cooling system and the stator low-temperature cooling system at the same time. The design of the stepped stator coil and the rotor coil can effectively utilize the internal space of the superconducting motor, and improves the electromagnetic parameters of the motor at the same time.

Description

Technical Field

[0001] The present invention relates to the field of motors, and in particular to a MW-class fully superconducting synchronous motor based on a stepped superconducting coil. Background Art

[0002] Driven by the global transformation of energy structures, building efficient, compact, and low-loss power systems has become a core proposition for breaking through energy technology bottlenecks. Superconducting motors, with their near-zero resistance characteristics, can significantly reduce winding losses (>50% reduction compared to traditional motors). Their power density (>15kW / kg) and operating efficiency (>99%) demonstrate disruptive potential in scenarios such as aerospace all-electric propulsion, integrated ship power systems, and offshore wind turbines exceeding MW. However, existing superconducting motor technology still faces two core challenges: first, performance degradation caused by the electromagnetic-thermal-mechanical multi-physics coupling effect under complex operating conditions; second, the systematic contradiction between the extremely low temperature environment of superconducting materials and the demand for high power output.

[0003] Specifically, traditional superconducting motors mostly use a uniform coil layout with a significant technical defect: first, there is magnetic field distortion and harmonic loss. The uniform turns distribution leads to an aggravated end magnetic leakage effect, and the high-order harmonics of the air gap magnetic field account for more than 15% (especially the 5th and 7th harmonics), causing additional iron loss and eddy current loss (the total loss accounts for >5% of the rated power); second, there is a contradiction between space utilization and power density. Due to the critical bending radius of the superconducting tape, conventional ring / racetrack-shaped coils are difficult to achieve a three-dimensional compact arrangement, resulting in the effective winding space accounting for less than 50%, and the power density has long stagnated at 10MW / m 3 Magnitude. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a MW-class fully superconducting synchronous motor based on a stepped superconducting coil, including a stepped stator superconducting winding, a stepped rotor superconducting winding, a stator low-temperature sealing system, a rotor dynamic low-temperature sealing system, and a superconducting motor vacuum sealing system, to address the problem of superconducting coil performance degradation caused by magnetic field distortion and improve operating efficiency and space utilization.

[0005] In order to achieve the above-mentioned objectives, the technical solution of the present invention is as follows: a MW-class fully superconducting synchronous motor based on a stepped superconducting coil comprises: a stator superconducting winding, a rotor superconducting winding, a stator cryogenic sealing system, a rotor dynamic cryogenic sealing system, and a superconducting motor vacuum sealing system; the stator cryogenic sealing system and the rotor dynamic cryogenic sealing system respectively provide a working environment in a superconducting temperature zone for the stator superconducting winding and the rotor superconducting winding, and the vacuum sealing system provides a thermally insulating working environment for the stator cryogenic sealing system and the rotor dynamic cryogenic sealing system.

[0006] The beneficial effects of this invention lie in providing a fully superconducting, high-intensity magnetic field through the stepped design of the stator and rotor superconducting coils, optimizing the space utilization of the superconducting motor and enabling higher power output within a limited volume, resulting in superior space and energy efficiency. Furthermore, the low-temperature cavity and vacuum structure, designed in a coordinated manner to take into account the operating temperature range of the superconducting material, significantly reduces heat transfer from external heat sources to the superconducting coils, ensuring that the superconducting coils maintain a stable low-temperature state and effectively reducing performance degradation caused by temperature fluctuations or instabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0008] Figure 1 Schematic diagram of a stator superconducting winding and a rotor superconducting winding according to an embodiment of the present invention;

[0009] Figure 2 This is an axial cross-sectional view of a superconducting winding according to an embodiment of the present invention;

[0010] Figure 3 This is a radial cross-sectional view of a MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to an embodiment of the present invention;

[0011] Figure 4 2 is a diagram of a low temperature and vacuum system according to an embodiment of the present invention.

[0012] In the figure, the reference numerals are: stator superconducting winding 1, rotor superconducting winding 2, stator cryogenic sealing system 3, rotor dynamic cryogenic sealing system 4, vacuum sealing system 5, outer skeleton 11, inner skeleton 12, outer stator double-cake superconducting coil 13, inner stator double-cake superconducting coil 14, outer skeleton 21, inner skeleton 22, outer rotor double-cake superconducting coil 23, inner rotor double-cake superconducting coil 24, stator cryogenic cavity 32, solenoid valve 311, pressure relief valve 312, cryogenic pump 34, PID temperature control Module 35, cryogenic temperature sensor 331, pressure sensor 332, external support frame 36, solenoid valve 411, pressure relief valve 412, interlayer flow channel 42, rotor cryogenic cavity 43, central flow channel 44, pressure sensor 461, cryogenic temperature sensor 462, flow rate sensor 463, cryogenic pump 47, insulated torque tube 491, magnetic fluid sealing structure 492, rotating shaft 493, vacuum outlet 51, magnetic fluid sealing structure 52, vacuum cavity 53, vacuum pump 54, vacuum gauge 55. DETAILED DESCRIPTION

[0013] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. To achieve the above-mentioned objectives, the present invention adopts the following technical solutions.

[0014] like Figure 1 As shown, a MW-class all-superconducting synchronous motor based on a stepped superconducting coil according to an embodiment of the present invention includes a stepped stator superconducting winding 1, a stepped rotor superconducting winding 2, a stator cryogenic sealing system 3, a rotor dynamic cryogenic sealing system 4, and a vacuum sealing system 5. The vacuum sealing system 5 provides a thermally insulated working environment for the stator cryogenic sealing system 3 and the rotor dynamic cryogenic sealing system 4.

[0015] like Figure 1 As shown, the stator cryogenic sealing system 3 and the rotor dynamic cryogenic sealing system 4 of this embodiment of the present invention provide superconducting temperature range operating environments for the stator superconducting winding 1 and the rotor superconducting winding 2, respectively. The stator superconducting winding 1 maintains a low-temperature operating environment below 77K through the stator cryogenic sealing system 3, while the rotor superconducting winding 2 achieves stable low-temperature cooling under high-speed rotation conditions through the rotor dynamic cryogenic sealing system 4. The vacuum sealing system 5 provides a high-vacuum isolation environment between the stator and rotor cryogenic systems, reducing the impact of external heat loads on the superconducting coils.

[0016] like Figure 2 As shown, the stator superconducting winding 1 of this embodiment of the present invention is specifically composed of nine sets of outer stator double-pancake superconducting coils 13 and nine sets of inner stator double-pancake superconducting coils 14. The outer stator double-pancake superconducting coils 13 have a greater number of turns per layer than the inner stator double-pancake superconducting coils 14, forming a radially stepped arrangement. The stator superconducting winding 1's outer and inner frames 11 and 12 are welded to the inner wall of the stator low-temperature cavity 32 using a high-strength aluminum alloy. This ensures the relative position and stepped shape of the windings, preventing them from changing due to electromagnetic forces and other external forces, and ensuring the winding's geometric stability under electromagnetic forces. The outer stator double-pancake superconducting coils 13 are wound in a racetrack shape using high-critical current density YBCO superconducting tape. The outer stator double-pancake superconducting coils 13 have a progressively increased number of turns compared to the inner stator double-pancake superconducting coils 14 to enhance the radial component of the main magnetic field. The inner stator's 14 twin superconducting coils have decreasing turns. Stator conductor slots guide the superconducting tape evenly along the axial direction, minimizing end magnetic flux leakage. Adjacent coils are connected in series via superconducting-superconducting joints, and the stator superconducting current leads are led through the conductor slots to the external power supply system.

[0017] like Figure 2As shown, the rotor superconducting winding 2 of this embodiment of the present invention consists of six sets of outer rotor double-pancake superconducting coils 23 and six sets of inner rotor double-pancake superconducting coils 24. The outer rotor double-pancake superconducting coils 23 have 20% fewer turns than the inner rotor double-pancake superconducting coils 24, creating a reverse step magnetic field. The outer rotor double-pancake superconducting coils 23 use a low-turn design to reduce centrifugal stress, while the inner rotor double-pancake superconducting coils 24 use a high-turn layout to suppress air gap magnetic field harmonics. They are connected in series via rotor superconducting-superconducting joints. Current is input from the rotor superconducting current lead through the center flow channel, and the superconducting-superconducting joints are used to connect the coils in series. The high-turn inner rotor double-pancake superconducting coils 24 generate a stronger magnetic potential, and their magnetic field must pass through the outer rotor double-pancake superconducting coils 23 and a larger air gap path to reach the stator. The low-turn outer rotor double-pancake superconducting coils 23 have fewer turns, but their magnetic field acts more directly on the air gap. This "strong inside, weak outside" magnetic potential distribution, through the difference in the number of turns ratio, can optimize the resulting magnetic field waveform in the air gap, making it closer to a sine wave. While maintaining the required total ampere-turns or current density, reducing the number of turns in the outer rotor double-pancake superconducting coil 23 allows for the replacement of superconducting tape with a larger cross-section and higher critical current safety, directly improving the ability to resist quenching. The outer skeleton 21 and inner skeleton 22 of the rotor superconducting winding 2 are welded using titanium alloy. The outer skeleton 21 is welded to the rotating shaft 493 and the inner wall of the rotor low-temperature cavity 43. Current is input through the rotor superconducting current lead through the central flow channel.

[0018] like Figure 3 As shown, the outer wall of the stator low-temperature cavity 32 of the embodiment of the present invention is welded with an external support structure 36 for connecting to the inner wall of the vacuum cavity 53. The rotor dynamic low-temperature sealing system 4 of the embodiment of the present invention is installed on the shaft 493 through an insulated torque tube 491 (thermal conductivity <1×10 -4 W / m·K) isolates heat conduction between the stator and rotor. In this embodiment of the present invention, a magnetic fluid seal structure 492 is installed at the junction of the rotating shaft 493 and the vacuum chamber. A magnetic fluid seal structure 52 is also installed at the junction of the vacuum port and the vacuum chamber. Using Fe3O4 nanofluid, it achieves zero leakage at a speed of 5000 rpm.

[0019] like Figure 3 、 Figure 4As shown, the stator cryogenic sealing system 3 of this embodiment of the present invention includes a solenoid valve 311, a pressure relief valve 312, a stator cryogenic cavity 32, a cryopump 34, a PID temperature control module 35, a cryogenic temperature sensor 331, a pressure sensor 332, an external support frame 36, and a cooling medium. Specifically, the solenoid valve 311 and the pressure relief valve 312 are respectively installed at the inlet and outlet of the axial end of the stator cryogenic cavity 32. The cooling medium, driven by the cryopump 34, enters the stator cryogenic cavity 32 through the solenoid valve 311, circulates along the annular flow channel of the external support frame 36, absorbs heat from the stator superconducting winding 1, and then returns to the storage tank through the pressure relief valve 312. The cryogenic temperature sensor 331 and the pressure sensor 332 are installed inside the stator cryogenic cavity 32 near the end of the stator superconducting winding 1 to monitor the temperature and pressure in real time. The PID temperature control module 35 stabilizes the temperature within the superconducting coil operating temperature range by adjusting the opening of the solenoid valve 311 and the speed of the cryopump 34. The pressure is controlled between 0.3 and 0.5 MPa. The pressure relief valve 312 automatically opens when the pressure exceeds the limit to ensure system safety.

[0020] like Figure 3 、 Figure 4 As shown, the rotor cryogenic sealing system 4 according to an embodiment of the present invention includes a solenoid valve 411, a pressure relief valve 412, a rotor cryogenic cavity 43, a cooling medium, a pressure sensor 461, a cryogenic temperature sensor 462, a flow rate sensor 463, a cryogenic pump 47, a PID temperature control module 35, an adiabatic torque tube 491, a magnetic fluid sealing structure 492, and a bearing 493. The solenoid valve 411 is installed at the inlet of the interlayer flow channel 42, the pressure relief valve 412 is installed at the outlet of the central flow channel 44, and the pressure sensor 461 is installed within the rotor cryogenic cavity 43. Specifically, the cryogenic temperature sensor 462 and the flow rate sensor 463 are both installed on the inner wall of the rotor cryogenic cavity 43 at the end of the rotor superconducting winding 2. The cooling medium is dynamically transferred through the interlayer flow channel 42 and the central flow channel 44. The cooling medium enters the rotor cryogenic cavity 43 under the control of the solenoid valve 411, is centrifugally distributed along the spiral flow path of the interlayer flow channel 42, cools the rotor superconducting winding 2, and then flows back through the central flow channel 44. The insulated torque tube is installed at the connection between the stator low-temperature cavity 43 and the bearing. The flow rate sensor 463 and the low-temperature temperature sensor 462 work together to provide feedback to the PID temperature control module 35, dynamically adjusting the flow rate of the solenoid valve 411 to maintain the temperature of the rotor superconducting winding 2 within the superconducting coil operating temperature range. A cryogenic pump 47 drives the refrigerant through the solenoid valve 411 into the interlayer flow channel 42 and the stator low-temperature cavity 43. The refrigerant circulates along the annular interlayer flow channel 42 of the outer support frame, absorbing heat before returning to the storage tank through the central flow channel 44.

[0021] like Figure 3 、 Figure 4As shown, the low-temperature temperature sensor 462, flow rate sensor 463, and pressure sensor 461 located in the rotor low-temperature cavity 43 of the embodiment of the present invention monitor the status of the rotor low-temperature cavity 43 in real time. The PID temperature control module 35 stabilizes the rotor temperature in the working temperature zone and controls the pressure at 0.3-0.5 MPa by adjusting the opening of the solenoid valve 411 and the pump speed. When the flow rate difference of the refrigerant medium relative to the stepped rotor superconducting winding 2 is too large or overpressure occurs, the pressure relief valve 412 responds to pressure relief within 0.1s.

[0022] like Figure 3 、 Figure 4 As shown in FIG. 1 , the vacuum sealing system 5 of the embodiment of the present invention is composed of a vacuum port 51, a vacuum cavity 53, a magnetic fluid sealing structure 52, a vacuum pump 54, and a vacuum gauge 55. The vacuum gauge 55 is installed inside the vacuum cavity 53. The vacuum port is connected to the vacuum pump 54. When the rotor rotates at high speed, the vacuum is continuously drawn to make the cavity vacuum ≤1×10 -4 Pa, reducing heat transfer from gas molecules. A magnetic fluid seal structure 52 is installed at the vacuum port 51, utilizing a gradient magnetic field to secure the nano-magnetic fluid. A dynamic sealing gap of less than 50 μm ensures vacuum fluctuations of less than ±5% even at high-speed rotation, achieving dynamic sealing and vacuum maintenance. A vacuum cavity 53 encloses the entire stator cryogenic cavity 43, connected by a high-strength alloy skeleton. Ultimately, this achieves low-temperature stability and high power density operation for the entire system.

Claims

1. A MW-class all-superconducting synchronous motor based on stepped superconducting coils, characterized by: include: Stator superconducting windings, rotor superconducting windings, stator cryogenic sealing systems, rotor dynamic cryogenic sealing systems, and superconducting motor vacuum sealing systems; The stator cryogenic sealing system and the rotor dynamic cryogenic sealing system provide a working environment in the superconducting temperature zone for the stator superconducting winding and the rotor superconducting winding respectively, and the vacuum sealing system provides an insulating working environment for the stator cryogenic sealing system and the rotor dynamic cryogenic sealing system.

2. A MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 1, characterized in that: The stepped stator superconducting winding includes a stator winding outer frame, a stator winding inner frame, multiple outer-layer stator double-pancake superconducting coils, and multiple inner-layer stator double-pancake superconducting coils. The number of turns between the layers of the outer-layer stator double-pancake superconducting coils is greater than the number of turns between the layers of the inner-layer stator double-pancake superconducting coils. The stator superconducting winding is fixed by welding the stator outer frame and the inner frame. The coils are connected using stator superconducting-superconducting joints, and the stator superconducting current leads are transmitted through wire slots.

3. The MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 1, characterized in that: The rotor superconducting winding includes a rotor winding outer frame, a rotor winding inner frame, multiple outer rotor double-pancake superconducting coils, and multiple inner rotor double-pancake superconducting coils. The outer rotor double-pancake superconducting coil has fewer turns than the inner rotor double-pancake superconducting coil. It is fixed by welding the outer frame and the inner frame. The coils are connected using rotor superconducting-superconducting joints and are powered by rotor superconducting current leads.

4. A MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 1, characterized in that: The stator low-temperature cooling system includes: a solenoid valve, a pressure relief valve, a stator low-temperature cavity, a cryogenic pump, an external support frame and a cooling medium. The solenoid valve and the pressure relief valve are respectively installed at the inlet and outlet of the axial end of the stator low-temperature cavity. The cooling medium is driven by the cryogenic pump, enters the stator low-temperature cavity through the solenoid valve, circulates along the annular flow channel of the external support frame, absorbs the heat of the stator superconducting winding, and then returns to the storage tank through the pressure relief valve.

5. A MW-class fully superconducting synchronous motor based on a stepped superconducting coil as claimed in claim 4, characterized in that: The stator cryogenic cooling system also includes: a cryogenic temperature sensor, a pressure sensor, and a PID temperature control system. The cryogenic temperature sensor and pressure sensor are installed inside the stator cryogenic cavity near the end of the stator superconducting winding to monitor the temperature and pressure status in real time. The PID temperature control module stabilizes the temperature in the superconducting coil working temperature zone by adjusting the solenoid valve opening and the cryogenic pump speed.

6. The MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 1, characterized in that: The rotor dynamic cryogenic cooling system includes: a solenoid valve, a pressure relief valve, an interlayer flow channel, a rotor cryogenic cavity, a central flow channel, a cooling medium, a pressure sensor, a cryogenic temperature sensor, a flow rate sensor, a cryogenic pump, and a PID temperature control system; the solenoid valve is installed at the inlet of the interlayer flow channel, the pressure relief valve is installed at the outlet of the central flow channel, the pressure sensor is installed inside the rotor cryogenic cavity, and the cryogenic temperature sensor and the flow rate sensor are both installed on the inner wall of the rotor cryogenic cavity at the end of the rotor superconducting winding. The cooling medium is dynamically transmitted through the interlayer flow channel and the central flow channel. The cooling medium is controlled by the solenoid valve to enter the rotor cryogenic cavity, and is centrifugally distributed along the spiral flow channel of the interlayer flow channel. After cooling the rotor superconducting winding, it flows back through the central flow channel.

7. A MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 6, characterized in that: The flow rate sensor and the cryogenic temperature sensor work together to feed back data to the PID temperature control system, dynamically adjusting the solenoid valve flow to maintain the temperature of the rotor superconducting winding within the superconducting coil operating temperature zone; the refrigerant medium is driven by a cryogenic pump through the solenoid valve into the interlayer flow channel and the stator low-temperature cavity, circulates along the annular interlayer flow channel of the external support frame, absorbs heat, and then returns to the storage tank from the central flow channel.

8. The MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 6, characterized in that: The thermal insulation torque tube is installed at the connection between the stator low-temperature cavity and the bearing.

9. The MW-class fully superconducting synchronous motor based on a stepped superconducting coil according to claim 1, characterized in that: The vacuum sealing system consists of a vacuum port, a vacuum cavity, a magnetic fluid sealing structure, a vacuum pump and a vacuum gauge. The vacuum gauge is installed inside the vacuum cavity. The vacuum port is connected to the vacuum pump. The magnetic fluid sealing structure is installed on the vacuum port. The vacuum cavity wraps the stator low-temperature cavity.

10. A MW-class all-superconducting synchronous motor based on a stepped superconducting coil according to claim 9, characterized in that: The vacuum cavity and the stator low-temperature cavity are connected by a high-strength alloy skeleton.

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