Variable flux memory motor and shaftless rim underwater propeller

Abstract

The invention discloses a variable flux memory motor and a shaftless rim underwater thruster, the motor comprises a stator, an armature winding, a rotor, a plurality of low-coercivity permanent magnets and a plurality of high-coercivity permanent magnets, the armature winding adopts a twelve-phase winding, the low-coercivity permanent magnets and the high-coercivity permanent magnets are embedded into the rotor and are alternately distributed in the circumferential direction; the low-coercivity permanent magnets are arranged on the rotor in a manner of extending in the circumferential direction, the magnetizing direction of the low-coercivity permanent magnets is radial magnetizing, and the magnetizing directions of any two adjacent low-coercivity permanent magnets are opposite; the high-coercivity permanent magnets are arranged on the rotor in a manner of extending in the radial direction, the magnetizing directions of the high-coercivity permanent magnets are tangential in the circumferential direction, and the magnetizing directions of any two adjacent high-coercivity permanent magnets are opposite; when the motor operates, the magnetization state of the low-coercivity permanent magnet is changed by applying d-axis current. According to the invention, dynamic adjustment of the magnetic flux of the motor is realized, and the operation efficiency and stability of the motor are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet synchronous motors, and in particular relates to a variable flux memory motor and a shaftless rim underwater propeller. Background Art

[0002] Permanent magnet motors have been widely used in various electric drive systems due to their high efficiency, reliability and low maintenance costs. Traditional permanent magnet motors usually use permanent magnets with fixed magnetic fields. Once manufactured, their magnetic properties are difficult to adjust and cannot meet the dynamic flux regulation requirements in some special application scenarios. However, with the continuous development of modern industrial technology, certain application scenarios (such as vehicle drive systems, ship propulsion systems, and high-efficiency motors) have increasingly higher performance requirements for motors, especially under different load and speed conditions. The motor needs to be able to flexibly adjust the flux to achieve higher energy efficiency and performance optimization.

[0003] The variable flux memory motor is an innovative motor design that uses permanent magnet materials with different coercive forces in the rotor and combines them with a specific magnetic circuit design to achieve dynamic regulation of the magnetic flux. This type of motor can change the magnetization state of the low coercive force permanent magnet through an externally applied current, thereby flexibly controlling the motor's magnetic flux. This feature of the variable flux memory motor gives it a significant advantage in applications that require a wide speed range, high efficiency, and low noise.

[0004] The shaftless rim thruster is an advanced propulsion technology that has gradually emerged in the field of ship and underwater propulsion in recent years. Unlike traditional shaft-driven thrusters, the shaftless rim thruster eliminates the traditional mechanical transmission shaft and directly drives the rotor connected to the blades to rotate through the motor, thereby greatly reducing mechanical losses and maintenance requirements, and improving the overall efficiency and reliability of the system. In this thruster system, the use of a shaftless rim permanent magnet motor is an ideal choice. The shaftless rim permanent magnet motor not only provides efficient energy conversion, but also can adapt to the special needs of the underwater environment through its unique design, such as corrosion resistance, low noise and high thrust.

[0005] At present, the traditional shaftless rim permanent magnet motor still has some limitations in structure and performance, especially in how to optimize the flux regulation to meet the operating requirements under different working conditions. These motors usually adopt a fixed flux design, which makes it difficult to flexibly adjust the output characteristics of the motor under different operating conditions, resulting in low efficiency or large torque fluctuations in some cases. In addition, how to achieve more efficient and stable flux regulation in the shaftless rim thruster, thereby improving the overall performance of the thruster, is still a technical problem that needs to be solved urgently.

[0006] In addition, in the design of permanent magnet motors, the configuration of windings has a crucial impact on the performance of the motor. Although the traditional three-phase winding has a simple structure and low manufacturing cost, it often has problems such as large torque pulsation and high harmonic content in some high-performance applications, which easily lead to increased vibration and noise during motor operation. Summary of the invention

[0007] The main purpose of the present invention is to provide a variable flux memory motor and a shaftless rim underwater propeller to solve the problems of weak magnetic adjustment ability, limited high-efficiency operation area, and large torque pulsation of existing traditional underwater propulsion motors.

[0008] To achieve the aforementioned invention objectives, the technical solution adopted by the present invention includes: a variable flux memory motor, comprising a stator, an armature winding, a rotor and a permanent magnet, wherein the armature winding is wound on the stator and adopts a twelve-phase winding; the rotor is located on the inner side of the stator and rotates relative to the stator; the permanent magnet is embedded in the rotor, and comprises a plurality of low coercive force permanent magnets and a plurality of high coercive force permanent magnets, wherein the low coercive force permanent magnets and the high coercive force permanent magnets are alternately distributed in the circumferential direction; each of the low coercive force permanent magnets is extended in the circumferential direction on the rotor, and its magnetization direction is radial magnetization, and the magnetization directions of any two adjacent low coercive force permanent magnets are opposite; each of the high coercive force permanent magnets is extended in the radial direction on the rotor, and its magnetization direction is tangential magnetization along the circumference, and the magnetization directions of any two adjacent high coercive force permanent magnets are opposite; when the motor is running, by applying d The shaft current is used to change the magnetization state of the low coercive force permanent magnet, thereby dynamically adjusting the magnetic flux of the motor.

[0009] In a preferred embodiment, the twelve-phase winding is composed of four sets of Y-type connected three-phase windings that are sequentially phase-shifted by 15°.

[0010] In a preferred embodiment, the low-coercive force permanent magnets and the high-coercive force permanent magnets are evenly and alternately distributed in the circumferential direction, the low-coercive force permanent magnet is located between two adjacent high-coercive force permanent magnets along the circumferential direction, and is radially located in the middle of the high-coercive force permanent magnets.

[0011] In a preferred embodiment, by applying d The shaft current magnetizes or demagnetizes the low coercive force permanent magnet.

[0012] In a preferred embodiment, when the low coercive force permanent magnet is in a magnetized state, it forms a series magnetic circuit with the half of the high coercive force permanent magnet close to the inner side of the rotor, and forms a parallel magnetic circuit with the half of the high coercive force permanent magnet close to the air gap.

[0013] In a preferred embodiment, when the low coercive force permanent magnet is in a weak magnetic state, it forms a parallel magnetic circuit with the half of the high coercive force permanent magnet close to the air gap, and forms a short circuit with the half of the high coercive force permanent magnet close to the inner side of the rotor.

[0014] In a preferred embodiment, the ratio of the inner diameter of the rotor core to its radial thickness is greater than or equal to 2.5, which is suitable for a shaftless rim underwater propeller.

[0015] In a preferred embodiment, the material of the high coercive force permanent magnet is neodymium iron boron, and the material of the low coercive force permanent magnet is aluminum nickel cobalt.

[0016] On the other hand, the present invention also adopts another technical solution, including: a shaftless rim underwater propeller, including the above-mentioned variable flux memory motor and a blade connected to the variable flux memory motor.

[0017] In a preferred embodiment, the inner surface of the rotor of the variable flux memory motor is directly connected to the blades.

[0018] Compared with the prior art, the beneficial effects of the present invention are at least: 1. The motor of the present invention adopts a twelve-phase winding, which not only improves the reliability and fault tolerance of the motor, but also effectively reduces the torque pulsation of the motor, thereby reducing the vibration and noise during the operation of the motor.

[0019] 2. The structural arrangement design of the low coercive force permanent magnet and the high coercive force permanent magnet of the motor of the present invention can make the magnetic circuit in the motor rotor d The shaft current changes, and on the basis of the change of the magnetomotive force of the low coercive force permanent magnet, the magnetic regulation performance of the memory motor is further improved and the speed regulation range of the motor is expanded.

[0020] 3. The motor of the present invention adopts a larger inner diameter and core radial thickness ratio, which is suitable for shaftless rim underwater propellers. It eliminates the structural form of relying on the transmission shaft to provide rotational torque, and can directly generate a rotating magnetic field through the armature to drive the rotor connected to the blades to rotate, thereby greatly reducing the mechanical loss and maintenance requirements of the structure of the propeller system, and improving the overall efficiency and reliability of the system. In addition, the inner surface of the motor rotor can be directly connected to the blades, and directly contact the water flow when working underwater. When the motor is running, it can effectively reduce the rotor temperature and maintain the magnetic stability of the permanent magnet, thereby improving the stability and thermal performance of the motor.

[0021] 4. The motor of the present invention is suitable for fields such as ship propulsion, industrial automation and high-performance electric drive systems, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of the variable flux memory motor of the present invention; Figure 2 The motor of the present invention is in the magnetization state Figure 1 Schematic diagram of part A in the figure, where the arrow direction indicates the magnetization direction of the permanent magnet; Figure 3 The motor of the present invention is in a weak magnetic state. Figure 1 Schematic diagram of part A in the figure, where the arrow direction indicates the magnetization direction of the permanent magnet; Figure 4 The motor of the present invention is in the magnetization state Figure 1 Magnetic flux path diagram of local A in the middle; Figure 5 The motor of the present invention is in a weak magnetic state. Figure 1 Magnetic flux path diagram of local A in the middle; Figure 6 It is the air gap flux density waveform of the motor of the present invention when the motor is in the magnetization state and the weakening magnetic state.

[0024] Reference numerals: 1. stator, 11. stator teeth, 12. stator yoke, 2. armature winding, 3. rotor, 4. high coercive force permanent magnet, 41 and 42, two adjacent high coercive force permanent magnets, 5. low coercive force permanent magnet, 51 and 52, two adjacent low coercive force permanent magnets. DETAILED DESCRIPTION

[0025] The present invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are only exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as limiting, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in virtually any appropriate detailed embodiment.

[0026] The present invention discloses a variable flux memory motor and a shaftless rim underwater propeller, wherein the motor realizes dynamic regulation of the motor flux by adopting permanent magnet materials with different coercive forces and a twelve-phase winding, and further improves the operating efficiency and stability of the motor by optimizing the rotor structure and the winding phase layout, thereby providing technical support for the efficient operation of the shaftless rim propeller.

[0027] like Figure 1~Figure 3 As shown, a variable flux memory motor disclosed in an embodiment of the present invention specifically includes a stator 1, an armature winding 2, a rotor 3 and a permanent magnet, wherein the armature winding 2 is installed in the stator 1, the permanent magnet is embedded in the rotor, and the rotor 3 is located on the inner side of the stator 1 and rotates relative to the stator 1.

[0028] Specifically, in this embodiment, the stator 1 specifically includes a stator yoke 12 and a stator tooth 11. The stator yoke 12 is provided with stator slots (not shown), and the armature winding 2 is installed in the stator slots to generate induced electromotive force during the operation of the motor.

[0029] In order to reduce torque pulsation and harmonic distortion, the armature winding 2 of the present invention preferably adopts a twelve-phase winding design, which can be specifically composed of 4 sets of Y-type connected three-phase windings that are sequentially phase-shifted by 15°, and the armature winding is wound on the stator teeth 11. Using multiple sets of three-phase windings to form a twelve-phase winding, this winding configuration can effectively distribute the magnetic flux, which not only effectively reduces the torque pulsation of the motor, reduces the vibration and noise of the motor, but also when one of the windings fails, the motor can continue to operate, improves the fault tolerance and reliability of the motor, and ensures that the motor can still operate stably when some windings fail. In addition, the present invention adopts a twelve-phase winding, which reduces the complexity of the motor while enhancing the dynamic stability of the motor, and is suitable for applications requiring high efficiency and low noise.

[0030] Preferably, two permanent magnets of different materials are used in the rotor of the present invention, and the permanent magnets specifically include a plurality of high coercive force permanent magnets 4 and a plurality of low coercive force permanent magnets 5. The high coercive force permanent magnets 4 and the low coercive force permanent magnets 5 are alternately distributed in the circumferential direction of the rotor, that is, one high coercive force permanent magnet 4 is arranged with one low coercive force permanent magnet 5, and preferably uniformly and alternately distributed in the circumferential direction. The low coercive force permanent magnet 5 is located between two adjacent high coercive force permanent magnets 4 along the circumferential direction, and the radial position is located in the middle of the high coercive force permanent magnet 4, so as to better realize the magnetic flux regulation. When the low coercive force permanent magnet 5 is located in the middle position, the effect of variable magnetic circuit can be achieved in different magnetization states, further improving the magnetic adjustment range of the motor. During implementation, the high coercive force permanent magnet 4 is made of neodymium iron boron material, which has high remanence and coercive force, thereby providing a stable magnetic flux in the magnetized state. The low coercive force permanent magnet 5 is made of AlNiCo material and has a reversible magnetic change characteristic so that dThe shaft current pulse realizes rapid magnetization or demagnetization. In addition, the present invention embeds the permanent magnet inside the rotor 3. The built-in structure not only improves the stability of the motor under high-speed conditions, but also effectively expands the speed range by dynamically adjusting the magnetic flux, making the applicable working conditions of the motor of the present invention more extensive.

[0031] Each high coercive force permanent magnet 4 is radially extended on the rotor 3, and its magnetization direction is tangential magnetization along the circumference, and the magnetization directions of any two adjacent high coercive force permanent magnets 4 are opposite (e.g. Figure 2 Each low coercive force permanent magnet 5 is arranged on the rotor 3 in a circumferential direction, and its magnetization direction is radial magnetization, and the magnetization directions of any two adjacent low coercive force permanent magnets 5 are opposite (such as Figure 2 The low coercive force permanent magnet 51 and the low coercive force permanent magnet 52).

[0032] When the motor is running, by applying d The shaft current is used to change the magnetization state of the low coercive force permanent magnet 5, thereby dynamically adjusting the magnetic flux of the motor. Specifically, by applying d The shaft current can magnetize or demagnetize the low coercive force permanent magnet 5, and on the basis of the change of the magnetomotive force of the low coercive force permanent magnet 5, the magnetic modulation performance of the memory motor is further improved and the speed regulation range of the motor is expanded.

[0033] Specifically, Figure 4 As shown, in the initial state, the low coercive force permanent magnet 5 is in a magnetization state, and its magnetomotive force direction is the same as that of the high coercive force permanent magnet 4. At this time, the low coercive force permanent magnet 5 and the half of the high coercive force permanent magnet 4 close to the inner side of the rotor 3 form a series magnetic circuit, and the low coercive force permanent magnet 5 and the half of the high coercive force permanent magnet 4 close to the air gap form a parallel magnetic circuit. Figure 5 As shown, when the low coercive force permanent magnet 5 is applied d After the shaft demagnetization current pulse, the low coercive force permanent magnet 5 is in a weak magnetic state. At this time, the magnetomotive force direction of the low coercive force permanent magnet 5 is opposite to that of the high coercive force permanent magnet 4. The low coercive force permanent magnet 5 and the half of the high coercive force permanent magnet 4 close to the air gap form a parallel magnetic circuit. The magnetomotive force of the low coercive force permanent magnet 5 is opposite to the magnetomotive force of the half of the high coercive force permanent magnet 4 close to the inner side of the rotor 3, so that part of the magnetic flux of the high coercive force permanent magnet 4 is short-circuited, that is, it forms a short circuit with the half of the high coercive force permanent magnet 4 close to the inner side of the rotor. If a low speed and high torque working state is required, the motor can be further applied d The axial magnetizing current restores the magnetization state of the low coercive force permanent magnet 5 .

[0034] like Figure 6As shown, the air gap flux density waveform of the motor of the present invention is in the magnetization state and the weak magnetic state. It can be seen from the figure that the air gap flux density fundamental wave of the motor in the magnetization state is significantly higher than that in the low magnetization state, which proves that the proposed motor can achieve a wider magnetic adjustment range.

[0035] Preferably, the rotor core of the motor rotor 3 of the present invention adopts a larger inner diameter to radial thickness ratio, which is generally greater than or equal to 2.5, and is certainly not limited to greater than or equal to 2.5. It can be set according to actual conditions. In the radial direction, the rotor core inner diameter is larger to adapt to the rim structure. In the axial direction, the relative thickness of the rotor core can also be increased according to design requirements to compensate for the mechanical support requirements and magnetic flux distribution requirements brought about by the shaftless design, so that the motor is suitable for shaftless rim underwater propellers, eliminating the structural form of traditional underwater propellers that rely on the transmission shaft to provide rotational torque, and can directly generate a rotating magnetic field through the armature to drive the rotor connected to the blades to rotate.

[0036] The present invention also provides a shaftless rim underwater propeller, comprising the above-mentioned variable flux memory motor and a blade connected to the variable flux memory motor (not shown in the figure). Preferably, the inner surface of the rotor 3 can be directly connected to the blade and directly contact the water flow when working underwater, so that the rotor temperature can be effectively reduced when the motor is running, the magnetic stability of the permanent magnet can be maintained, and the stability of the motor and the propeller can be improved.

[0037] The present invention has the following advantages: 1. The motor of the present invention adopts a twelve-phase winding, which can not only improve the reliability and fault tolerance of the motor, but also effectively reduce the torque pulsation of the motor, thereby reducing the vibration and noise during the operation of the motor. 2. The structural arrangement design of the low-coercive force permanent magnet and the high-coercive force permanent magnet of the motor of the present invention can make the magnetic circuit in the motor rotor d The shaft current changes, and on the basis of the change in the magnetomotive force of the low coercive force permanent magnet, the magnetic modulation performance of the memory motor is further improved, and the speed regulation range of the motor is expanded. 3. The motor of the present invention adopts a larger inner diameter and core radial thickness ratio, which is suitable for shaftless rim underwater propellers, and eliminates the structural form of relying on the transmission shaft to provide rotational torque. It can directly generate a rotating magnetic field through the armature to drive the rotor connected to the blades to rotate, thereby improving the structure of the propeller system, greatly reducing mechanical losses and maintenance requirements, and improving the overall efficiency and reliability of the system. In addition, the inner surface of the motor rotor can be directly connected to the blades, and directly contacts the water flow when working underwater. When the motor is running, it can effectively reduce the rotor temperature and maintain the magnetic stability of the permanent magnet, thereby improving the stability and thermal performance of the motor. 4. The motor of the present invention is suitable for fields such as ship propulsion, industrial automation and high-performance electric drive systems, and has broad application prospects.

[0038] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0039] The use of headings and sections in this disclosure is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the disclosure.

Claims

1. A variable flux memory motor, characterized in that: The motor comprises a stator, an armature winding, a rotor and a permanent magnet, wherein the armature winding is wound on the stator and adopts a twelve-phase winding; the rotor is located on the inner side of the stator and rotates relative to the stator; the permanent magnet is embedded in the rotor and comprises a plurality of low-coercive force permanent magnets and a plurality of high-coercive force permanent magnets, wherein the low-coercive force permanent magnets and the high-coercive force permanent magnets are alternately distributed in the circumferential direction; each of the low-coercive force permanent magnets is extended in the circumferential direction on the rotor, and its magnetization direction is radial magnetization, and the magnetization directions of any two adjacent low-coercive force permanent magnets are opposite; each of the high-coercive force permanent magnets is extended in the radial direction on the rotor, and its magnetization direction is tangential magnetization along the circumference, and the magnetization directions of any two adjacent high-coercive force permanent magnets are opposite; when the motor is running, by applying d The shaft current is used to change the magnetization state of the low coercive force permanent magnet, thereby dynamically adjusting the magnetic flux of the motor.

2. The variable flux memory motor according to claim 1, characterized in that: The twelve-phase winding is composed of four sets of Y-type connected three-phase windings which are sequentially phase-shifted by 15°.

3. The variable flux memory motor according to claim 1, characterized in that: The low coercive force permanent magnets and the high coercive force permanent magnets are evenly and alternately distributed in the circumferential direction. The low coercive force permanent magnet is located between two adjacent high coercive force permanent magnets along the circumferential direction and radially located in the middle of the high coercive force permanent magnets.

4. The variable flux memory motor according to claim 1, characterized in that: By applying d The shaft current magnetizes or demagnetizes the low coercive force permanent magnet.

5. The variable flux memory motor according to claim 4, characterized in that: When the low coercive force permanent magnet is in a magnetized state, it forms a series magnetic circuit with the half of the high coercive force permanent magnet close to the inner side of the rotor, and forms a parallel magnetic circuit with the half of the high coercive force permanent magnet close to the air gap.

6. The variable flux memory motor according to claim 4, characterized in that: When the low coercive force permanent magnet is in a weak magnetic state, it forms a parallel magnetic circuit with the half of the high coercive force permanent magnet close to the air gap, and forms a short circuit with the half of the high coercive force permanent magnet close to the inner side of the rotor.

7. The variable flux memory motor according to claim 1, characterized in that: The ratio of the inner diameter of the rotor core of the rotor to its radial thickness is greater than or equal to 2.5, and the rotor is suitable for a shaftless rim underwater propeller.

8. The variable flux memory motor according to claim 1, characterized in that: The material of the high coercive force permanent magnet is neodymium iron boron, and the material of the low coercive force permanent magnet is aluminum nickel cobalt.

9. A shaftless rim underwater propeller, characterized in that: It comprises the variable flux memory motor as described in any one of claims 1 to 8 and a blade connected to the variable flux memory motor.

10. The shaftless rim underwater propeller according to claim 9, characterized in that: The inner surface of the rotor of the variable flux memory motor is directly connected to the blades.

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