Motor and control method thereof

Abstract

The invention provides a motor and a control method thereof, relates to the technical field of oil extraction equipment in an oil field, can accurately perform fault positioning through phase winding unit modular layout and independent lead design, and can also avoid fault diffusion in combination with an isolation structure. On the basis, when a fault occurs, power supply of a fault phase can be quickly locked and cut off, normal operation of other phases is maintained, operation continuity is greatly improved, production loss and maintenance cost are reduced, and fault-tolerant economy is improved. In addition, through modular design and ordered lead layout, motor assembly can be more standard, winding and lead connection of each unit can be completed in advance, then assembly can be performed, layout interference can be reduced, and assembly efficiency and precision can be improved. In conclusion, many defects of a traditional motor can be comprehensively overcome.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a high-reliability multiphase independent winding motor for downhole lifting systems and its fault-tolerant control method. Background Technology

[0002] Traditional electric motors typically use a star (Y) or delta (Δ) connection for their three-phase windings. The three-phase windings overlap and share a magnetic path on the stator core's magnetic circuit. Physically, the windings are closely adjacent in their slots or at their ends, without any dedicated physical structure (such as independent sector blocks or gaps) to spatially separate them. This design allows the magnetic field and heat between the three-phase windings to be directly transferred through the magnetic and thermal circuits, creating a three-phase shared magnetic circuit structure.

[0003] Because the three phases share a magnetic circuit and lack physical isolation, a fault in one phase can rapidly spread to other phases via magnetic and thermal coupling. For example, if an inter-turn short circuit occurs in one phase winding, the abnormal current generates a magnetic field that interferes with the magnetic circuits of other phases, causing current distortion in those phases. Simultaneously, the heat generated by the short circuit can affect the insulation performance of adjacent windings through thermal conduction. This cascading effect of a single-phase fault affecting multiple phases makes it impossible for the control system to isolate only the faulty phase while maintaining normal operation of the other phases, ultimately requiring a complete system shutdown to prevent the fault from escalating. Furthermore, current technologies rely on current amplitude thresholds for fault detection, requiring the current amplitude to stabilize and exceed the threshold before a judgment can be made. In some fault scenarios, such as minor inter-turn short circuits, the initial change in current amplitude may be small, requiring a period of accumulation to reach the threshold, leading to a delay in fault detection.

[0004] Furthermore, as downhole equipment becomes more compact and power-density, axial flux motors have emerged as a promising solution. However, when applied to extreme downhole environments, the heat dissipation design of the windings, phase-to-phase isolation, and rapid fault tolerance under this structure all present new technical challenges, for which existing technologies have failed to provide systematic solutions.

[0005] In summary, existing motors have shortcomings in terms of the independence of winding structure, the timeliness of fault detection, the economy of fault-tolerant design, and the effectiveness of thermal management. Summary of the Invention

[0006] The purpose of this invention is to provide a motor and its control method, which solves the core technical problems of existing motors in terms of winding coupling, fault detection, and fault-tolerant operation.

[0007] In a first aspect, embodiments of the present invention provide an electric motor, including a housing and a stator disposed within the housing. The stator is provided with multi-phase windings, wherein the multi-phase windings are physically isolated from each other and constitute multiple independent phase winding units; the start and end ends of each phase winding are independently led out to the terminals of the motor.

[0008] In conjunction with the first aspect, the present invention provides a first implementation of the first aspect, wherein the multiphase windings are wound on the stator in a layered staggered or fan-shaped distribution manner, so that the phase windings are spatially staggered.

[0009] In conjunction with the first aspect, the present invention provides a second implementation of the first aspect, wherein the layered staggered winding method is as follows: the multiphase winding includes a first coil segment and a second coil segment, the first coil segment and the second coil segment are wound in the circumferential direction of the stator with slot pitches staggered from the preset pole pitch, forming a relatively staggered distributed layout.

[0010] In conjunction with the first aspect, the present invention provides a third implementation of the first aspect, wherein the sector-shaped distribution winding method is: the multiphase winding consists of multiple sector-shaped coil blocks that are uniformly distributed on the stator disk surface and do not overlap, and are made of wire.

[0011] In conjunction with the first aspect, the present invention provides a fourth implementation of the first aspect, wherein the motor is a multi-disc series axial flux motor, and the stator is composed of multiple independent stator discs connected in series along the axial direction.

[0012] In conjunction with the first aspect, the present invention provides a fifth implementation of the first aspect, wherein each phase winding unit is isolated from each other by a preset isolation structure, and the preset isolation structure is made of a preset insulating and thermally conductive material.

[0013] In conjunction with the first aspect, the present invention provides a sixth embodiment of the first aspect, wherein the insulating and thermally conductive material includes nano-mica tape, micro heat pipe and / or thermally conductive insulating adhesive.

[0014] Secondly, embodiments of the present invention provide a motor control method, which is applied to a motor in any of the above embodiments. The method includes: monitoring the signals of the winding leads corresponding to each phase winding unit of the target motor to determine the current signal corresponding to each phase winding unit; determining the harmonic entropy value corresponding to each phase winding unit based on the current signal; determining the faulty phase of the target motor based on the harmonic entropy value; isolating the faulty phase; and controlling the target motor according to a preset operating control mode.

[0015] In conjunction with the second aspect, the present invention also provides a first implementation of the second aspect, wherein the step of determining the harmonic entropy value corresponding to each phase winding unit based on the current signal includes: performing a Fourier transform on the current signal to determine the fundamental wave and the corresponding main harmonic components of the current signal; and determining the harmonic entropy value corresponding to the current signal based on the fundamental wave and the main harmonic components.

[0016] In conjunction with the second aspect, the present invention also provides a second implementation of the second aspect, wherein the step of determining the faulty phase of the target motor based on the harmonic entropy value includes: determining whether the harmonic entropy value exceeds a preset entropy value threshold; if so, monitoring the duration of the harmonic entropy value; if the harmonic entropy value exceeds the preset entropy value threshold and the duration exceeds a preset time threshold, determining the phase corresponding to the harmonic entropy value as the faulty phase.

[0017] In conjunction with the second aspect, this embodiment of the invention also provides a third implementation of the second aspect, wherein the step of signal isolation of the faulty phase includes: cutting off the drive signal of the faulty phase to stop the faulty phase from outputting PWM signals, thereby performing signal isolation processing on the faulty phase; the step of motor control of the target motor according to a preset operation control mode includes: reconstructing the current current signal of the target motor to determine the current remaining corresponding reconstructed current of the target motor; reallocating the control target to the target motor based on the reconstructed current; generating an updated control mode based on the control target, and performing motor control of the target motor according to the control parameters corresponding to the updated control mode.

[0018] The embodiments of this invention bring the following beneficial effects: This invention provides a motor and its control method. The core structure of the motor adopts a modular design of multiple phase winding units. All phase winding units are evenly distributed along the circumference of the housing, breaking through the traditional layout mode where the three-phase windings of a motor overlap and share on the stator core. Each phase winding unit is physically separated through a preset isolation structure, forming its own independent and clearly defined spatial layout, thus severing the direct magnetic and thermal circuit connections between phase windings from the structural root. Simultaneously, each phase winding unit is equipped with independent winding leads, and these leads extend to both sides of the motor axis. Dedicated path planning ensures that the lead-out process of each phase lead is free from intersection and overlap, achieving an orderly and independent lead layout.

[0019] In summary, the embodiments of the present invention, through modular layout of phase winding units and independent lead design, can accurately locate faults, and the isolation structure can also prevent fault propagation. Based on this, when a fault occurs, the power supply to the faulty phase can be quickly located and cut off, maintaining the normal operation of other phases, significantly improving operational continuity, reducing production losses and maintenance costs, and enhancing fault-tolerant economics. Furthermore, the modular design and orderly lead layout of the embodiments of the present invention enable more standardized motor assembly; each unit can be pre-wound and lead-connected before assembly, reducing layout interference and improving assembly efficiency and accuracy. In conclusion, the embodiments of the present invention comprehensively address many shortcomings of traditional motors.

[0020] Other features and advantages of the invention will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the techniques described above.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of an electric motor provided in an embodiment of the present invention; Figure 2 A cross-sectional view of a radial motor stator structure provided in an embodiment of the present invention; Figure 3 A top view of a sector-shaped distribution of an axial motor winding provided in an embodiment of the present invention; Figure 4 A flowchart of a motor control method provided in an embodiment of the present invention; Figure 5 A schematic diagram of a motor system provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] This invention relates to a highly reliable three-phase motor and its fault-tolerant control method for downhole lifting systems such as submersible electric pumps, submersible screw pumps, and submersible plunger pumps, particularly suitable for harsh downhole environments with high temperatures and high pressures. The aim is to achieve phase isolation and decoupling through an innovative physical layout. Furthermore, it achieves triple decoupling of "magnetism-thermal-circuit" at the physical structure level, fundamentally improving the reliability of downhole lifting systems.

[0027] To facilitate understanding, we will first describe a motor provided in an embodiment of the present invention. Figure 1 A schematic diagram of the structure corresponding to an embodiment of the present invention is shown. The motor of this embodiment includes a housing 10 and a stator disposed within the housing 10, the stator having multi-phase windings. The multi-phase windings are physically isolated from each other, forming multiple independent phase winding units 20; Figure 1 The diagram illustrates the differentiating phase winding units, designated as phase winding units a-20a and b-20b. The housing serves as the external support and protection component of the motor, typically made of metal (such as aluminum alloy or cast iron), forming the motor's outer frame and creating a closed or semi-closed installation space. The phase winding unit is the core functional component that enables the conversion of electrical energy into magnetic energy. Each phase winding unit is made of enameled wire wound according to specific rules, corresponding to one phase of the motor (e.g., phase A, phase B, and phase C). Multiple phase winding units together constitute the motor's stator winding system. In this embodiment, each phase winding unit adopts a modular design, with each unit acting as an independent winding unit, evenly distributed along the circumference of the housing. Adjacent units maintain a fixed spacing, forming a symmetrical multi-phase layout.

[0028] Furthermore, in this embodiment of the invention, the start and end ends of each phase winding are independently led out to the wiring terminals of the motor. The winding leads are conductive components connecting the phase winding unit to the external control system, and can be composed of copper core wires and an insulating outer layer. Each phase winding unit is equipped with an independent lead group, including input and output leads. This embodiment of the invention adopts an independently led-out, bidirectional layout design, ensuring that the leads of each phase winding unit do not share channels with the leads of other units. The winding leads independently led out to both axial sides of the motor (i.e., the front and rear ends of the motor) can also achieve path planning through dedicated lead holes or lead slots on the housing, ensuring no crossing, friction, or interference between the leads. Based on this, the problem of chaotic lead layout in existing technologies can be solved, improving the reliability of electrical connections; simultaneously, the independent signal transmission channel makes it easier to detect abnormal electrical parameters of the faulty phase, avoiding the problem of fault signals being masked by other phase signals in traditional motors, and improving the timeliness and accuracy of fault detection.

[0029] Furthermore, in relation to the above embodiments, this invention also provides another type of motor to further illustrate the structure of the phase winding unit. Traditional motors often suffer from overlapping three-phase windings, leading to shared magnetic circuits, strong inter-phase magnetic coupling, and easy interference of one phase's current distortion with other phases. The motor of this invention may include an integral stator core. On this stator, through innovative winding and isolation processes, multiple phase winding units are formed that are physically, magnetically, and thermally isolated from each other. Each phase winding unit corresponds to one phase of the motor, and its winding's start (U1, V1, W1) and end (U2, V2, W2) are independently led out. The stator is the mounting carrier for the winding structure and can be made of stacked silicon steel sheets, extending along the motor axis to form a long strip structure. The winding structure consists of coils wound with insulated wires (such as copper enameled wire or aluminum enameled wire) in stator slots, generating a rotating magnetic field after alternating current is applied.

[0030] In this embodiment of the invention, each phase winding unit is isolated by a pre-set isolation structure to physically separate adjacent phase winding units, forming a physical barrier between units. The high magnetoresistance of the insulating material or air gap limits the magnetic field generated by each phase winding unit to its own region, preventing mutual magnetic field penetration and interference, and ensuring the independence of each phase's magnetic circuit. Furthermore, when using materials with excellent thermal insulation properties (such as ceramic fiber or polyimide), the high temperature generated by a faulty phase can be blocked from being conducted to adjacent units, protecting the insulation performance of adjacent windings. Further, the isolation structure can also position and fix each phase winding unit, preventing unit displacement due to vibration during operation and avoiding insulation wear caused by direct contact between winding ends. The above-mentioned isolation structure can take the form of insulating blocks, air gaps, or thermal insulation material layers, depending on actual needs. Its structural dimensions and materials must match the layout and operating parameters of the phase winding units.

[0031] In this embodiment of the invention, the stator 41 extends along the axial direction of the motor and has a preset length. This preset length can be designed based on preset usage requirements. This embodiment of the invention is designed with a corresponding motor for downhole operations. The length of the stator can be adapted to the installation space dimensions (such as the inner diameter and length limitations of the motor compartment of the downhole drilling tool) and power requirements of the corresponding downhole equipment, such as 1.2m-2.5m. This ensures that the motor output power meets the downhole operation requirements (such as driving the drill pipe to rotate at high speed) and is suitable for narrow downhole installation spaces, avoiding the motor being too large to be lowered into the well or to interfere with other components.

[0032] Furthermore, in a preferred embodiment of the present invention, the winding structures 42 of adjacent phase winding units 20 are staggered along the axial direction of the motor, that is, the winding coils of different phases have a displacement difference in the axial direction and are not coplanarly arranged. Based on this, the spatial distance between adjacent phase windings can be increased, the mutual influence of interphase leakage magnetic field can be reduced, and the magnetic field distribution can be made more uniform.

[0033] In this embodiment of the invention, the motor can be a radial motor (a traditional mainstream motor type with the magnetic field direction distributed radially along the motor) or an axial motor (a special motor with the magnetic field direction distributed axially along the motor) to adapt to the downhole lifting system. The downhole lifting system is a core piece of equipment in oil and gas extraction (such as pumping units, ESPs, screw pumps, etc.), and its working environment is characterized by confined space (limited casing inner diameter, typically 114-178mm), high temperature (downhole temperature 80-150℃), high pressure (10-30MPa), corrosive media (crude oil, brine), and large load fluctuations (crude oil viscosity changes, sand jamming risk). The radial motor in this embodiment focuses on high speed, standardization, and resistance to harsh environments, while the axial motor focuses on high power density, low speed and high torque, and thin design.

[0034] When the motor is a radial motor, the magnetic field is distributed radially (center to casing inner wall direction), which can be used as the mainstream power choice for downhole lifting systems (such as ESP lifting). It can directly drive the ESP impeller to rotate at high speeds (e.g., 3000-6000 rpm) to lift crude oil. Correspondingly, the stator length is adapted to the aforementioned preset length and extends along the motor axis (parallel to the casing axis). Furthermore, within the stator slots of the radial motor, the spacer is divided into a "lower layer" and an "upper layer" radially from the slot bottom to the slot opening. Each layer is separated by an insulating layer, forming a "double-layer" structure within the slot. The two effective sides of the same coil are placed in the upper and lower layers of different slots, so that the coils are distributed circumferentially according to the pole pitch, generating a rotating magnetic field. The winding structure of this embodiment includes a first coil segment 42-1 and a second coil segment 42-2 (corresponding to one layer of effective sides respectively). In a preferred embodiment of this invention, the first coil segment and the second coil segment are wound with approximately half a slot pitch offset in the circumferential direction of the stator to form a distributed layout and enhance the phase isolation effect. (Refer to...) Figure 2 The diagram shows a cross-sectional view of the stator structure corresponding to the radial motor. Figure 2 The first and second coil segments (e.g., 42-1, 42-2) are shown in cross-section. An isolation structure is set between the two coil segments, such as nano-mica tape 30-1 or micro heat pipe 30-2.

[0035] Unlike traditional concentrated windings (coils concentrated on a single stator tooth) and co-slot distributed windings, the first and second coil segments of this invention are wound at intervals of "slot pitch corresponding to a preset pole pitch" along the stator circumference, forming a non-concentrated, non-co-slot layered staggered winding method with a layer spacing of ≥2mm. Corresponding to downhole lifting systems, the aforementioned preset pole pitch can be designed according to the rated speed and torque requirements of the downhole motor (e.g., a U / V / W three-phase motor) (e.g., 4-pole or 6-pole electric submersible pump motors, with a pole pitch of π / 2 for 4-pole motors) to avoid efficiency degradation due to speed mismatch. In summary, the above spatial staggered design can significantly increase interphase magnetic reluctance, achieving magnetic circuit decoupling.

[0036] Furthermore, the independent winding structure and corresponding fault-tolerant method of the present invention are particularly suitable for downhole axial flux motors. Its core feature is that each phase winding consists of multiple sector-shaped coil blocks uniformly distributed and non-overlapping on the stator disk surface, made of flat copper wire (see [link to relevant documentation]). Figure 3 Isolation structures (such as thermally conductive insulating adhesive) are provided between each sector, achieving complete decoupling between the physical and magnetic circuits.

[0037] In this embodiment, each phase winding occupies an independent fan-shaped area on the disk, with a spacing much larger than the distance between layers in a radial motor. This large spatial distance naturally forms a physical "firewall," almost completely blocking the direct propagation path of phase-to-phase faults. Simultaneously, the magnetic reluctance between phases is increased to an extremely high level, and the mutual inductance coefficient is reduced to an extremely low level (e.g., <0.3), achieving extremely thorough magnetic circuit decoupling. Moreover, in this embodiment, the phase windings are physically separated, and heat sources are also isolated. Overheating in one phase is unlikely to directly affect adjacent phases through heat conduction. Furthermore, the fully exposed winding ends provide ideal conditions for heat dissipation, resulting in extremely high heat dissipation efficiency.

[0038] As a particularly preferred embodiment of the present invention, a multi-disc series structure can be adopted to adapt to the narrow space downhole and achieve power expansion. The stator of the motor is composed of multiple independent stator discs connected in series coaxially, with rotor discs arranged alternately. The sector windings on each disc constitute an independent phase winding unit or part of a unit. This modular design not only facilitates flexible adjustment of the motor length and power according to the well depth, but also the inherent axial gap between the discs themselves constitutes an excellent natural isolation channel, further enhancing the decoupling effect between the thermal and magnetic circuits.

[0039] Furthermore, the corresponding windings are neatly led out from both sides of the axis or laterally via independent leads and connected to the frequency converter.

[0040] In summary, the axial motor of this embodiment of the invention forms a disc-shaped distributed winding structure with multiple phase winding units, each stator corresponding to an independent region, achieving physical separation of each phase winding in the stator space. This partitioned layout clearly defines the installation and operation areas of each phase winding, reducing direct contact and interference between phases from a structural perspective. Furthermore, the small size of a single stator disc facilitates operation by automated winding equipment. Simultaneously, if a stator disc winding malfunctions, it can be replaced individually without scrapping the entire stator, reducing production and maintenance costs.

[0041] In summary, each phase winding unit in this embodiment of the invention, through the aforementioned spatial misalignment and physical isolation design, reduces magnetic and thermal coupling between phases, providing structural support for independent motor control and fault isolation. For the special operating conditions of downhole lifting systems (such as pumping units, ESPs, etc.) (high temperature, high pressure, limited space, large load fluctuations, and extremely high reliability requirements), the radial motor in this embodiment of the invention, based on its compact radial layout, reduces installation space requirements. Furthermore, based on its stable torque output characteristics, it can achieve low-speed, high-torque output, adapting to the harsh mechanical environment and space constraints of downhole systems. The axial motor, with its rotor end face directly serving as a heat dissipation surface, facilitates the setting of axial heat dissipation channels, making it suitable for high-temperature downhole environments. Combined with the modular axial splicing stator design of this embodiment of the invention, power adjustment (e.g., 10~20kW) can be achieved. Compared to a pure radial motor, it has stronger adaptability and higher magnetic flux utilization, effectively improving electromagnetic efficiency. In summary, the embodiments of the present invention can meet the lifting requirements of different well depths (500~3000m) and different production volumes (5~50 tons / day), thereby reducing the cost of customized motors and improving product versatility.

[0042] Furthermore, addressing the issue of fault propagation in traditional motors, this invention employs a pre-designed isolation structure to treat each phase winding as an independent functional unit. Even if a short circuit or insulation damage occurs in a phase, the fault range can be limited through physical and electromagnetic barriers, preventing complete motor failure. The isolation structure can be made of a pre-designed insulating and thermally conductive material. In the axial motor implementation, this material can be filled between each sector of the coil. In the radial motor implementation, it can be filled between each layer of the winding.

[0043] The insulating and thermally conductive materials may include nano-mica tape, micro heat pipes, and / or thermally conductive insulating adhesive. Nano-mica tape has a thermal conductivity of 5 W / mK and an insulation strength of 28 kV / mm, exhibiting excellent insulation and thermal conductivity. Micro heat pipes (e.g., Φ2 mm) can also be embedded between layers, forming efficient heat dissipation channels together with the nano-mica tape to achieve thermal decoupling. Nano-mica tape can be used as interphase insulation spacers between the sector winding blocks, providing extremely high electrical insulation strength and preventing interphase creepage. Its excellent axial thermal conductivity can also be utilized to direct the heat generated during winding operation towards the stator disk plane.

[0044] Furthermore, for any of the above embodiments, the isolation structure and heat dissipation scheme of the motor can be designed as an integrated unit. For example, the motor can be designed as an oil-filled structure, allowing insulating cooling oil to fill the internal cavity of the motor, directly immersing all winding units. Heat is transferred to the casing through convection and thermal conduction, and finally carried away by the well fluid. Alternatively, micro heat pipes can be embedded between the winding layers or within the stator, or nano-mica tape or highly thermally conductive insulating materials such as thermally conductive insulating adhesive can be used. These methods all serve the functions of isolation and heat dissipation.

[0045] Furthermore, microchannel cooling channels can be fabricated inside or on the back of the stator disk, allowing coolant to flow through and carry away heat. This micro heat pipe can also be embedded inside the stator disk, with its evaporation end close to the heat source (winding) and its condensation end connected to the cooling channel or the housing. In this embodiment, because the phase windings are physically separated, their heat sources are also isolated. Heat generated by one phase winding due to overload or other reasons is unlikely to directly affect adjacent phases through heat conduction, achieving excellent thermal decoupling.

[0046] In summary, the embodiments of the present invention have constructed a winding system that is spatially independent, signal-independent, and fault-isolated by optimizing the winding method to reduce magnetic coupling, independently enhancing end monitoring, and isolating structures to block faults. This not only improves the stability of the motor during normal operation but also provides hardware support for fault detection and fault-tolerant control.

[0047] It should be noted that the core "multi-phase independent winding" structure of this invention is also applicable to switched reluctance motors. In this type of motor, the concentrated windings of each phase on the stator salient poles are physically isolated from each other, and the start and end points of each phase winding are independently led out to achieve independent control. The large physical gap between the stator salient poles, along with the heat-conducting oil, insulating varnish, or encapsulating adhesive that may be filled in between, together constitute the aforementioned "isolation structure," which can effectively reduce thermal and magnetic coupling between phases. Therefore, the structural fault-tolerant solution provided by this invention is also applicable to switched reluctance motors.

[0048] Furthermore, based on the above embodiments, this invention also provides a motor control method, which describes the fault detection and fault-tolerant control of the aforementioned motor. Corresponding to the above embodiments, the winding leads are key nodes for current signal acquisition; traditional motors connect via a common terminal, leading to signal coupling. In this invention, the two ends of the winding structure of each phase winding unit are independently led out, and the beginning and end of each phase winding are not connected to other phases, forming an independent electrical circuit, ensuring that the acquired current signal only reflects the operating state of that phase itself. The current end can also be directly used as the mounting point for a current sensor, resulting in a short signal path, low interference, and accurate capture of subtle changes in the current of each phase to provide reliable raw data. Correspondingly, this invention, through signal acquisition and fault-tolerant control, achieves the core advantages of early fault detection, accurate location, rapid isolation, and stable fault tolerance, significantly improving reliability and continuous operation capability compared to existing technologies. (Refer to...) Figure 4 The method includes the following steps: Step S102: Monitor the signals of the winding leads corresponding to each phase winding unit of the target motor to determine the current signal corresponding to each phase winding unit.

[0049] In this embodiment of the invention, each phase winding of the target motor is led out from both ends and is physically / electromagnetically isolated, allowing for independent acquisition of current signals for each phase (e.g., each phase is equipped with a dedicated Hall sensor or Rogowski coil). This avoids signal coupling interference caused by traditional common-terminal connections, ensuring that the current signal reflects only the true state of a single phase. Combined with the relatively staggered distributed winding method, inter-phase magnetic coupling is reduced, minimizing magnetic field interference between non-faulty phases and faulty phases. This allows the acquired current signal to more accurately reflect the electrical characteristics of the winding in that phase (e.g., harmonic distortion during inter-turn short circuits).

[0050] Step S104: Determine the harmonic entropy value corresponding to each phase winding unit based on the current signal.

[0051] Step S106: Determine the faulty phase of the target motor based on the harmonic entropy value.

[0052] Unlike traditional methods that rely on a single indicator of current amplitude, this invention calculates harmonic entropy values ​​to transform the fundamental and higher harmonic energy distributions of the current signal into complex quantifiable values. Harmonic entropy values ​​are sensitive to subtle distortions in the current waveform (such as fluctuations in the proportion of harmonic energy caused by magnetic circuit imbalance), allowing for detection before a fault develops to the point of exceeding current amplitude limits. Identifying potential faults by allowing entropy values ​​to deviate from a reference range solves the problem of delayed response to early faults in traditional methods.

[0053] Furthermore, due to the independent winding structure, the harmonic distortion of the faulty phase (such as the surge of the 3rd and 5th harmonics caused by inter-turn short circuits) will significantly change its harmonic entropy value, while the healthy phase is minimally affected, making the fault characteristics more specific.

[0054] In one implementation, a threshold comparison or duration can be used to determine the faulty phase. For example, the magnitude and duration of the harmonic entropy exceeding the limit (e.g., >50ms) can be combined for judgment to avoid misjudgment caused by instantaneous load fluctuations. Simultaneously, because the winding isolation in this embodiment of the invention is strong, a single-phase signal anomaly will not contaminate other phases, allowing for precise location of the faulty phase without the need for complex multi-phase cross-verification. During normal operation, the independent magnetic circuit of the winding ensures stable and small differences in the harmonic entropy values ​​of each phase, allowing for the establishment of precise phase-specific reference ranges, further improving the accuracy of fault determination.

[0055] Step S108: Isolate the faulty phase and control the target motor according to the preset operation control mode.

[0056] Combined with the physical isolation design of the windings, the PWM output of the faulty phase can be quickly blocked using solid-state relays or IGBT modules (response time ≤ 50ms). After isolation, the faulty phase can be completely disconnected from the power supply, preventing the fault from escalating. Furthermore, because the magnetic circuits of the remaining healthy phase windings are independent and have low coupling, the torque and excitation components of the motor can be redistributed, allowing the motor to operate in other pre-set operating control modes. This achieves fault-tolerant control of the motor and solves the problem of magnetic field disorder and unstable operation after a fault in traditional shared magnetic circuit motors.

[0057] The above embodiments utilize a relatively staggered distributed winding method (the winding structures of adjacent phase winding units are staggered along the motor's axial direction) to make the multi-phase windings of the motor physically and electrically independent. Combined with a preset isolation structure, this spatially isolates each phase winding, structurally severing the shared magnetic circuit path between phases and reducing inter-phase thermal / magnetic coupling. Even if a single-point fault occurs in one phase, physical isolation prevents the fault from propagating to other phases, avoiding shutdown due to a single-point fault. This invention introduces harmonic entropy as a fault detection indicator for the motor, not relying on a single current amplitude threshold. By analyzing the uniformity of harmonic energy distribution in the current signal, it quantifies the changes in current harmonic characteristics caused by winding faults, achieving real-time and accurate fault identification. Furthermore, this invention achieves fault tolerance based on fault phase signal isolation and preset operating control mode switching, allowing the motor to continue operating after fault phase isolation, improving the motor's reliability and continuous operation capability.

[0058] Furthermore, this embodiment of the invention also provides another motor control method, which is used to provide a detailed explanation of the calculation of harmonic entropy values. Specifically, the method includes the following steps: Step S202: Monitor the signal of the winding lead corresponding to each phase winding unit of the target motor to determine the current signal corresponding to each phase winding unit.

[0059] Step S204: Perform a Fourier transform on the current signal to determine the fundamental frequency and corresponding main harmonic components of the current signal.

[0060] Step S206: Determine the harmonic entropy value corresponding to the current signal based on the fundamental frequency and the main harmonic components.

[0061] The fundamental frequency is used to characterize the frequency component corresponding to the synchronous speed of the motor, while harmonic components include higher-order harmonic components such as the 3rd, 5th, 7th, and 11th harmonics. By performing a Fast Fourier Transform (FFT) on the acquired current signal of each phase, the current signal in the time domain is converted into a signal in the frequency domain, thereby decomposing the fundamental frequency and the main harmonic components of the current signal.

[0062] Furthermore, the energy ratio of the fundamental wave and the main harmonic components is used as the basis for calculation, and substituted into the harmonic entropy model formula (H). x (H) x = -Σ (I k / I1) 2 · ln(I k / I1)), where I k I1 is the amplitude of the k-th harmonic current and I2 is the amplitude of the fundamental current. The harmonic entropy of each phase current is calculated in real time to quantify the uniformity and complexity of the current harmonic energy distribution.

[0063] Step S208: Based on the harmonic entropy value, determine the faulty phase of the target motor.

[0064] Based on the above embodiments, it can be determined whether the harmonic entropy value exceeds a preset entropy threshold. If so, the duration of the harmonic entropy value is monitored. If the harmonic entropy value exceeds the preset entropy threshold and the duration exceeds a preset time threshold, the phase corresponding to the harmonic entropy value is identified as the faulty phase. For example, a certain phase H... x If the value is >0.25 and persists for 10ms, the phase is considered to have experienced an early failure.

[0065] Step S210: Isolate the faulty phase and control the target motor according to the preset operation control mode.

[0066] In one implementation, the faulty phase can be isolated by cutting off its drive signal, thus stopping the output of its PWM signal. Further, the motor's operating mode can be switched (e.g., switching a three-phase motor to two-phase operation) to allow it to continue operating in the new mode. In another implementation, the current signal of the target motor can be reconstructed to determine the remaining corresponding reconstructed current. Based on the reconstructed current, a control target is reallocated to the target motor. An updated control mode is generated based on the control target, and the target motor is controlled according to the control parameters corresponding to the updated control mode. Correspondingly, a current reconstruction algorithm based on the Clarke transform (Iα = I...) can be used. - (1 / 2)*I - (1 / 2)*I Iβ = (√3 / 2)*(I - I )) Maintain operation, and the output power can be maintained at over 72%.

[0067] Furthermore, based on the above-described motor embodiments, this invention also provides a motor system equipped with a protector and a downhole frequency converter module to achieve motor control. Figure 5 A schematic diagram of the motor system is shown. In both architectures described above, the start and end points of the windings are independently led out, forming corresponding leads (e.g., the U, V, and W phases contain six leads), providing a physical basis for fault-tolerant control. Furthermore, these leads are connected to an downhole frequency converter, which has independent bridge arm outputs, allowing for independent driving, monitoring, and control of each phase winding.

[0068] This invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described... Figure 4 The steps of the method are shown. Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the above-described steps. Figure 4 The steps of the method are shown. This invention also provides a schematic diagram of the structure of an electronic device, as shown. Figure 6 The diagram shows the structure of the electronic device, which includes a processor 101 and a memory 100. The memory 100 stores computer-executable instructions that can be executed by the processor 101. The processor 101 executes the computer-executable instructions to implement the above-mentioned... Figure 4 The method shown. In Figure 6In the illustrated embodiment, the electronic device further includes a bus 102 and a communication interface 103, wherein the processor 101, the communication interface 103, and the memory 100 are connected via the bus 102. The memory 100 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk drive. Communication between this system network element and at least one other network element is achieved through at least one communication interface 103 (which can be wired or wireless), and can utilize the Internet, wide area network, local area network, metropolitan area network, etc. Bus 102 can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, or an AMBA (Advanced Microcontroller Bus Architecture) bus. AMBA defines three types of buses: APB (Advanced Peripheral Bus), AHB (Advanced High-performance Bus), and AXI (Advanced deXtensible Interface). Bus 102 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0069] Processor 101 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 101 or by instructions in software form. Processor 101 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory. The processor 101 reads the information in the memory and, in conjunction with its hardware, completes the aforementioned task. Figure 4 The method shown.

[0070] The computer program product of a motor and its control method provided in this embodiment of the invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. Specific implementations can be found in the method embodiments, and will not be repeated here. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system described above can be referred to the corresponding process in the preceding method embodiments, and will not be repeated here. Furthermore, in the description of this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0071] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Finally, it should be noted that the above embodiments are merely specific implementations of the invention, used to illustrate the technical solutions of the invention, and not to limit it. The scope of protection of the invention is not limited thereto. Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in this invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this invention, and should all be covered within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. An electric motor, comprising a housing and a stator disposed within the housing, wherein the stator is provided with multi-phase windings, characterized in that: The multiphase windings are physically isolated from each other, forming multiple independent phase winding units; The start and end of each phase winding are independently led out to the terminals of the motor.

2. The motor according to claim 1, characterized in that, The multiphase windings are wound on the stator in a layered staggered or fan-shaped distribution, so that the phase windings are spatially staggered.

3. The motor according to claim 2, characterized in that, The layered misaligned winding method is as follows: The multiphase winding includes a first coil segment and a second coil segment. The first coil segment and the second coil segment are wound in the circumferential direction of the stator with slot pitches corresponding to preset pole pitches, forming a relatively staggered distributed layout.

4. The motor according to claim 2, characterized in that, The fan-shaped distribution winding method is as follows: The multiphase winding consists of multiple sector-shaped coil blocks that are evenly distributed on the disk surface of the stator and do not overlap, and are made of wire.

5. The motor according to claim 4, characterized in that, The motor is a multi-disc series axial flux motor, and the stator is composed of multiple independent stator discs connected coaxially in series along the axial direction.

6. The motor according to claim 1, characterized in that, Each phase winding unit is isolated from the others by a preset isolation structure, which is made of a preset insulating and thermally conductive material.

7. The motor according to claim 6, characterized in that, The insulating and thermally conductive materials include nano-mica tape, micro heat pipes, and / or thermally conductive insulating adhesive.

8. A motor control method, characterized in that, The method is applied to the motor according to any one of claims 1-6, and the method includes: Signal monitoring is performed on the winding leads corresponding to each phase winding unit of the target motor to determine the current signal corresponding to each phase winding unit. Based on the current signal, determine the harmonic entropy value corresponding to each phase winding unit; Based on the harmonic entropy value, the faulty phase of the target motor is determined; The faulty phase is isolated from the signal, and the target motor is controlled according to the preset operation control mode.

9. The method according to claim 8, characterized in that, The step of determining the harmonic entropy value corresponding to each phase winding unit based on the current signal includes: Perform a Fourier transform on the current signal to determine the fundamental frequency and corresponding main harmonic components of the current signal; Based on the fundamental frequency and the main harmonic components, the harmonic entropy value corresponding to the current signal is determined.

10. The method according to claim 8, characterized in that, The step of determining the faulty phase of the target motor based on the harmonic entropy value includes: Determine whether the harmonic entropy value exceeds a preset entropy threshold; if so, monitor the duration of the harmonic entropy value. If the harmonic entropy value exceeds the preset entropy threshold, and the duration exceeds the preset time threshold, the phase corresponding to the harmonic entropy value is determined as the faulty phase.

11. The method according to claim 8, characterized in that, The step of isolating the faulty phase includes: The drive signal of the faulty phase is cut off, so that the faulty phase stops outputting the PWM signal, thereby performing signal isolation processing on the faulty phase; The steps of controlling the target motor according to the preset operation control mode include: The current signal of the target motor is reconstructed to determine the current remaining corresponding reconstructed current of the target motor. Based on the reconfigured current, the control target is reassigned to the target motor; An updated control mode is generated based on the control objective, and the target motor is controlled according to the control parameters corresponding to the updated control mode.

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