High-fault-tolerance axial variable flux permanent magnet synchronous motor for deep sea

Abstract

The invention relates to the technical field of permanent magnet synchronous motors, in particular to a deep-sea high-fault-tolerance axial variable flux permanent magnet synchronous motor, which comprises a stator assembly including a coaxially arranged stator iron core, a stator winding embedded in a stator iron core groove, and a flux adjusting winding arranged on the radial inner side of the stator iron core; the rotor assembly comprises axial rotor discs and radial rotor discs which are symmetrically arranged, permanent magnets with the same polarity are attached to the outer surfaces of the axial rotor discs at intervals, iron core protrusions are formed between the adjacent permanent magnets, the polarities of the permanent magnets of the two axial rotor discs are opposite, and the iron core protrusions are arranged in a staggered mode; the adjustable magnetic windings and the permanent magnets form a parallel magnetic circuit structure, and magnetic flux generated by the adjustable magnetic windings sequentially passes through the stator iron core, the iron core protrusions of the axial rotor disc and the radial rotor disc to form a closed loop. The air gap magnetic flux is dynamically controlled through the axial hybrid excitation structure, the magnetic field is actively weakened to suppress the fault during short circuit, and the excitation is enhanced to improve the power density and efficiency during non-fault.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a high-fault-tolerant axial variable magnetic flux permanent magnet synchronous motor for deep-sea use. Background Art

[0002] Deep-sea operating equipment (including unmanned submersibles, seabed miners, and observation robots) must maintain long-term stable operation in high-pressure (>1,000 meters deep), low-temperature, and highly corrosive deep-sea environments. This places stringent demands on the operational reliability, power density, and fault tolerance of the drive motors. Traditional permanent magnet synchronous motors face three technical bottlenecks in this application scenario: First, the uncontrollable characteristics of permanent magnet excitation: when a short-circuit fault occurs in the armature winding, the constant strong magnetic field continuously generated by the permanent magnet will cause the short-circuit current to increase irreversibly, triggering the winding thermal accumulation effect and secondary fault chain reaction.

[0003] Second, the limitation of the single fault-tolerant mechanism: existing technologies mainly rely on redundant winding configurations or complex physical isolation structures, which significantly increase the size and weight of the motor and make it difficult to meet the compact structural design requirements of deep-sea equipment.

[0004] Third, the dynamic response characteristics are insufficient: Faced with the frequent load changes in deep-sea operations (such as sudden jamming of the robotic arm), the fixed-field motor lacks the ability to quickly adjust the torque, which can easily cause mechanical system shock or operational instability.

[0005] Current technical approaches to improving motor fault tolerance mainly focus on the following areas, but all suffer from defects in adaptability to deep-sea environments: (1) Multi-phase redundant motor technology: Fault reconstruction is achieved through multi-phase winding configurations such as six-phase and nine-phase windings. However, due to the high-pressure sealing conditions in the deep sea, the complexity of multi-phase cable wiring and the difficulty of heat dissipation increase exponentially.

[0006] (2) Mechanical magnetic field adjustment technology: Mechanical devices such as permanent magnet displacement mechanisms are used to adjust the air gap magnetic flux, but the risk of mechanical jamming and sealing failure increases significantly in high-voltage environments.

[0007] (3) Pure electric excitation synchronous motor technology: Although the controllability of the magnetic field is improved by eliminating permanent magnets, its excitation loss is too high and the power density is insufficient, which makes it difficult to meet the lightweight and high-efficiency requirements of deep-sea equipment.

[0008] To address these technical bottlenecks, this paper innovatively proposes a collaborative design of an axial flux permanent magnet synchronous motor and dynamic excitation control. By combining the modular topology advantages of the axial flux motor with the real-time flux control capabilities of the excitation winding, it effectively addresses the technical contradiction between high fault tolerance and high torque density in motor systems operating under extreme deep-sea conditions, filling a technological gap in this field. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention discloses a highly fault-tolerant axial variable-flux permanent magnet synchronous motor for deep-sea operation. This motor incorporates independent excitation windings, creating a hybrid excitation topology that dynamically adjusts the air gap flux. During a fault, the excitation current is adjusted to weaken the magnetic field, reducing short-circuit currents and iron losses, thereby preventing further fault expansion. During normal operation, the magnetic field is enhanced, improving power density and efficiency. This achieves the goal of "fail-safe capacity reduction and normal high-efficiency operation," enhancing the reliability and environmental adaptability of deep-sea motors.

[0010] The present invention is achieved through the following technical solutions: The present invention provides a high fault-tolerant axial variable flux permanent magnet synchronous motor for deep sea use, comprising The stator assembly comprises a coaxially arranged stator core, a stator winding embedded in the stator core slots, and a magnetic tuning winding arranged radially inward of the stator core; The rotor assembly comprises symmetrically arranged axial rotor discs and radial rotor discs, wherein permanent magnets of the same polarity are attached to the outer surfaces of the axial rotor discs at intervals, and iron core protrusions are formed between adjacent permanent magnets. The permanent magnets of the two axial rotor discs have opposite polarities and the iron core protrusions are arranged in a staggered manner; The magnetic flux regulating winding and the permanent magnet form a parallel magnetic circuit structure. The magnetic flux generated by the magnetic flux regulating winding passes through the stator core, the core protrusions of the two axial rotor disks and the radial rotor disk in sequence to form a closed loop.

[0011] Furthermore, the permanent magnets are surface mounted, circumferentially adjacent permanent magnets have the same polarity, and each permanent magnet is axially symmetrically arranged with the opposite rotor core protrusion.

[0012] Furthermore, the two axial rotor disks are connected via an inner ring magnetic conductive structure, and the magnetic permeability of the core protrusion is higher than the magnetic permeability of the permanent magnet.

[0013] Furthermore, the excitation magnetic circuit of the field modulation winding is independent of the working magnetic circuit of the stator winding, and the magnetic flux generated by the field modulation winding is transmitted through the main air gap area.

[0014] Furthermore, when a short-circuit fault of the armature winding is detected, the magnetic flux regulating winding applies a reverse current to weaken the air gap flux; under normal operating conditions, the magnetic flux regulating winding applies a unidirectional current to enhance the air gap flux.

[0015] Furthermore, the stator core adopts a modular segmented structure, and each segment of the stator core corresponds to an independent excitation control unit.

[0016] Furthermore, no permanent magnet is provided on the surface of the radial rotor disk as a magnetic connection component of the axial rotor disk magnetic circuit.

[0017] Furthermore, the magnetic potential amplitude of the magnetic regulating winding can be dynamically adjusted, and the adjustment response time is less than 10ms.

[0018] Furthermore, the control method of the synchronous motor includes the following steps: Real-time monitoring of armature winding current and temperature parameters; When the short-circuit fault feature is detected, a reverse current is injected into the magnetic winding to reduce the air gap flux intensity to 0 at the maximum; Under sudden load changes, the direction of the magnetic winding current is dynamically adjusted to maintain a constant output torque.

[0019] Furthermore, a current sensor is used to measure the current signal in real time and extract the current characteristic signal. When a current anomaly caused by a high-voltage winding fault is detected, excitation current compensation is automatically triggered.

[0020] The beneficial effects of the present invention are: This invention implements dynamic control of the air gap flux density by implanting an independent field winding in an axial flux permanent magnet synchronous motor, creating an axial hybrid excitation topology. When an armature winding short-circuit fault is detected, the motor actively implements air gap field weakening control by adjusting the field winding current intensity in real time. This effectively suppresses the amplitude of the short-circuit circulating current and core eddy current losses, preventing the fault from spreading. Simultaneously, based on non-fault operating conditions, the motor establishes an auxiliary magnetic field by increasing the excitation current, significantly improving the motor's power density and operating efficiency.

[0021] The present invention effectively enhances the operating reliability and environmental adaptability of deep-sea motors under complex working conditions through a dual-mode intelligent switching mechanism of "safe capacity reduction in fault conditions and efficient operation under rated working conditions". 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a diagram of an axial variable flux permanent magnet synchronous motor according to the present invention; Figure 2 Schematic diagram of the main magnetic circuit and demagnetization magnetic circuit according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the main magnetic circuit and the magnetizing magnetic circuit according to an embodiment of the present invention; Figure 4 is a schematic diagram of a rotor core with protrusions according to an embodiment of the present invention; Figure 5Schematic diagram of a stator core with magnetic tuning winding slots according to an embodiment of the present invention; Figure 6 This is an exploded diagram of the overall structure of the axial variable flux permanent magnet synchronous motor; Figure 7 Schematic diagram of magnetic tuning winding according to an embodiment of the present invention; Figure 8 is the permanent magnet arrangement diagram; The numbers in the figure represent: 1. Rotor core; 2 (1) N-pole permanent magnet; 2 (2) S-pole permanent magnet; 3 (1) N-pole stator winding; 3 (2) S-pole stator winding; 4. Field modulation winding; 5. Stator core. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] In one embodiment, referring to Figure 1 and Figure 6 As shown, the axial variable flux permanent magnet synchronous motor structure includes: a rotor core (see Figure 4 As shown), permanent magnet (participate in Figure 8 As shown), stator winding, field winding, stator core (see Figure 5 The stator part adopts axially symmetrical distribution of laminated silicon steel sheets, including stator core, stator winding and magnetic winding. The stator winding adopts three-phase distributed winding and is evenly arranged along the circumference. Figure 7 The magnetic field adjustment winding shown is powered by an independent power supply to achieve magnetic field adjustment; the rotor part is laminated and formed by high-magnetic-permeability electrical steel, and includes a rotor core, N-pole permanent magnets and S-pole permanent magnets. The permanent magnets are made of high-coercive-force neodymium iron boron material.

[0026] Reference Figure 2 and Figure 3 As shown, the rotor core of this embodiment is designed as an axisymmetric structure, and grooves for installing permanent magnets are evenly distributed on its surface along the circumferential direction. The N-pole permanent magnets and S-pole permanent magnets are alternately attached to the grooves of the rotor core to form alternating N poles and S poles, and core protrusions are formed between adjacent permanent magnets to enhance the magnetic conductivity of the magnetic circuit.

[0027] In this embodiment, the stator core also utilizes a laminated silicon steel sheet structure, symmetrically distributed along the axial direction. Its inner circumference is uniformly defined with slots for the stator windings. The stator windings utilize a three-phase distributed winding system, evenly spaced along the circumference of the stator core to provide three-phase power to the motor. The magnetic field tuning winding is located radially inward of the stator core and powered by an independent power supply, enabling dynamic adjustment of the magnetic field.

[0028] This embodiment further adopts the following technical features to optimize the magnetic circuit structure and improve the performance of the motor: 1. The permanent magnets are surface-mounted, with adjacent circumferential permanent magnets having the same polarity and each permanent magnet symmetrically arranged with the opposite rotor core protrusion. This mounting method not only simplifies the motor structure but also improves permanent magnet utilization and uniformity of the motor's magnetic flux density.

[0029] Second, the two axial rotor discs are connected by an inner ring magnetic structure, and the magnetic permeability of the core protrusion is higher than that of the permanent magnets. This design helps to enhance the magnetic conductivity of the magnetic circuit and improve the efficiency and power density of the motor.

[0030] Third, the excitation magnetic circuit of the field-tuning winding is independent of the operating magnetic circuit of the stator winding. The magnetic flux generated by the field-tuning winding is transmitted through the main air gap area. This design enables the field-tuning winding to operate independently of the stator winding, achieving precise control of the magnetic field.

[0031] Fourth, the stator core adopts a modular segmented structure, with each stator core segment corresponding to an independent excitation control unit. This design not only improves the maintainability and scalability of the motor, but also facilitates independent control and optimization of each motor part.

[0032] Fifth, the radial rotor disks are not equipped with permanent magnets, which serve as magnetic connection components for the axial rotor disk magnetic circuit. This design simplifies the rotor structure, reduces manufacturing costs, and also helps improve the reliability and stability of the motor.

[0033] 6. The magnetic potential amplitude of the magnetic winding can be dynamically adjusted, with an adjustment response time of less than 10ms. This rapid response capability enables the motor to quickly adapt to load changes, improving the motor's dynamic performance and stability.

[0034] In this embodiment, the rotor core comprises two outer rotor disks for axial motors and one inner rotor disk for radial motors, all coaxially connected via high-strength, non-magnetic bolts. The axial permanent magnets are all surface-mounted, with the polarity of the permanent magnets on one side being identical and spaced proportionally with the protrusions on the rotor core. The permanent magnets and the protrusions on the opposite rotor core form a hybrid axial-radial magnetic circuit. The inner rotor disk of the radial motor has no permanent magnets and serves only to conduct magnetic field and form a closed magnetic circuit. A rectangular slot is provided on the inner side of the stator core, within which a magnetic tuning winding is wound using double-layer insulated copper wire. The winding ends are sealed with epoxy resin.

[0035] This embodiment of the water jet motor not only optimizes the mechanical structure of the operating lever, but also significantly improves operational fluidity and gear clarity through the combination of a memory spring and steel balls. This careful design detail reflects the inventor's deep technical expertise in the field of drive motors for deep-sea equipment and their unparalleled focus on user experience. In practical applications, this water jet motor can stably and reliably complete various deep-sea operations, providing strong technical support for deep-sea exploration and development.

[0036] This embodiment constructs a main magnetic circuit system using permanent magnets, a rotor core, and a stator core. Circumferentially adjacent permanent magnets maintain the same polarity configuration, while adjacent rotor core salient poles will induce opposite polarity. The rotor permanent magnets on both sides exhibit opposite polarity and are symmetrically distributed. Each forms a parallel magnetic shunt with the corresponding air gap, armature winding, and part of the stator core. The two parallel magnetic circuits form independent closed loops along the circumference of the stator core, maintaining magnetic isolation from each other.

[0037] The magnetic field winding is controlled by an independent power supply system, allowing for flexible adjustment of the magnetic field strength and direction. During normal motor operation, the magnetic field winding and permanent magnets interact with the air gap to form an enhanced main magnetic circuit, effectively improving the motor's power density and operating efficiency. In the event of a motor short circuit, the magnetic field winding responds quickly by applying a reverse current to weaken the air gap flux, effectively curbing the growth of the short-circuit current and protecting the motor from further damage.

[0038] This embodiment generates additional magnetic flux in the same or opposite direction as the main magnetic circuit by applying excitation currents in different directions to the central stator magnetic winding. Given that the rotor core utilizes an alternating arrangement of silicon steel salient poles and permanent magnets, and the significantly superior magnetic permeability of the silicon steel sheet material to that of the permanent magnets, the magnetic flux generated by the magnetic winding is primarily conducted through the silicon steel sheet structure, thereby achieving flux regulation. Under conditions requiring high torque output, the system utilizes a magnetizing magnetic circuit configuration; when operating in a field-weakening, speed-expanding mode, it switches to a demagnetizing magnetic circuit configuration.

[0039] Furthermore, in this embodiment, the additional magnetic flux generated by the field-tuning winding is not limited to conduction through the rotor core protrusions. It also cleverly utilizes the radial rotor disk as a magnetic connection component of the magnetic circuit, further enhancing the efficiency and flexibility of magnetic flux regulation. Although the radial rotor disk lacks permanent magnets, its magnetic conductivity ensures smooth conversion of magnetic flux between the axial and radial directions, providing a solid guarantee for the stable operation of the motor.

[0040] In this embodiment, the DC excitation winding of the axial variable flux motor is securely mounted radially inward of the stator core, achieving a brushless motor structure. The motor's two rotors utilize spaced permanent magnets, connected by an inner ring. The rotor core poles are arranged in a slot-like structure, and the poles on the two rotor sections are staggered. Furthermore, the polarity of the permanent magnets on these two rotor sections is opposite to that on the stator side.

[0041] In this embodiment, the magnetic circuits of the electric excitation and permanent magnet excitation of the axial variable flux motor are connected in parallel. This design effectively avoids the risk of demagnetization of the permanent magnets. The electric excitation magnetic potential only passes through the main air gap of the motor and does not pass through other additional air gaps. Therefore, the magnetic resistance of the magnetic circuit is relatively small, which helps to effectively reduce the required excitation current. The magnetic circuit of the electric excitation magnetic potential passes through the stator core and passes through the iron core poles on the two rotors respectively, and then forms a closed loop through the inner ring of the rotor core.

[0042] In summary, the present invention implements dynamic control of the air gap flux density by implanting an independent excitation winding in an axial flux permanent magnet synchronous motor, constructing an axial hybrid excitation topology. When an armature winding short-circuit fault is detected, the motor actively implements air gap field weakening control by real-time regulation of the excitation winding current intensity, effectively suppressing the short-circuit circulating current amplitude and core eddy current losses, preventing the fault from spreading. Simultaneously, based on the requirements of non-fault operating conditions, the motor's power density and operating efficiency are significantly improved by enhancing the excitation current to establish an auxiliary magnetic field.

[0043] The present invention effectively enhances the operating reliability and environmental adaptability of deep-sea motors under complex working conditions through a dual-mode intelligent switching mechanism of "safe capacity reduction in fault conditions and efficient operation under rated working conditions".

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high fault-tolerant axial variable flux permanent magnet synchronous motor for deep sea use, characterized in that: include The stator assembly comprises a coaxially arranged stator core, a stator winding embedded in the stator core slots, and a magnetic tuning winding arranged radially inward of the stator core; The rotor assembly comprises symmetrically arranged axial rotor discs and radial rotor discs, wherein permanent magnets of the same polarity are attached to the outer surfaces of the axial rotor discs at intervals, and iron core protrusions are formed between adjacent permanent magnets. The permanent magnets of the two axial rotor discs have opposite polarities and the iron core protrusions are arranged in a staggered manner; The magnetic flux regulating winding and the permanent magnet form a parallel magnetic circuit structure. The magnetic flux generated by the magnetic flux regulating winding passes through the stator core, the core protrusions of the two axial rotor disks and the radial rotor disk in sequence to form a closed loop.

2. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1 is characterized in that: The permanent magnets are surface mounted, circumferentially adjacent permanent magnets have the same polarity, and each permanent magnet is axially symmetrically arranged with the opposite rotor core protrusion.

3. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: The two axial rotor disks are connected via an inner ring magnetic conductive structure, and the magnetic permeability of the core protrusion is higher than the magnetic permeability of the permanent magnet.

4. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: The excitation magnetic circuit of the field modulation winding is independent of the working magnetic circuit of the stator winding, and the magnetic flux generated by the field modulation winding is transmitted through the main air gap area.

5. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: When a short-circuit fault in the armature winding is detected, a reverse current is applied to the field winding to weaken the air gap flux; Under normal operating conditions, the magnetic winding applies current in the same direction to enhance the air gap flux.

6. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: The stator core adopts a modular segmented structure, and each segment of the stator core corresponds to an independent excitation control unit.

7. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: The surface of the radial rotor disk is not provided with permanent magnets, which serve as magnetic connection components of the axial rotor disk magnetic circuit.

8. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 1, characterized in that: The magnetic potential amplitude of the magnetic regulating winding can be dynamically adjusted, and its adjustment response time is less than 10ms.

9. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to any one of claims 1 to 8, characterized in that: The control method of the synchronous motor comprises the following steps: Real-time monitoring of armature winding current and temperature parameters; When the short-circuit fault feature is detected, a reverse current is injected into the magnetic winding to reduce the air gap flux intensity to 0 at the maximum; Under sudden load changes, the direction of the magnetic winding current is dynamically adjusted to maintain a constant output torque.

10. The deep-sea high fault-tolerant axial variable flux permanent magnet synchronous motor according to claim 9, characterized in that: A current sensor is used to measure the current signal in real time and extract the current characteristic signal. When a current anomaly caused by a high-voltage winding fault is detected, excitation current compensation is automatically triggered.

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