A permanent magnet synchronous drive assembly with speed change function

Abstract

The present invention provides a permanent magnet synchronous drive assembly with a speed change function, which includes a hybrid excitation motor, a reducer, a dual-channel inverter, a controller, and a sensor network; the hybrid excitation motor includes a stator and a rotor configured as a fractional slot winding, the rotor being provided with a permanent magnet array, an isolation layer, and an excitation winding array in sequence from the axis outward and also distributed in sequence along the rotor axis, the permanent magnet array being spliced ​​from a plurality of fan-shaped magnetic steels, and the N poles and the S poles being arranged alternately to form a main magnetic field pole pair; the number of excitation windings in the excitation winding array is half the number of magnetic steels, and each winding is respectively embedded between adjacent pole pairs, the axis of the excitation winding is offset at a certain angle from the axis of the permanent magnet pole to form a spatial phase difference, and the permanent magnet magnetic circuit formed by the permanent magnet array and the stator and the electric excitation magnetic circuit formed by the excitation winding array and the stator are vectorially superimposed at the air gap; the dual-channel inverter includes a main power channel and an excitation channel.

Description

Technical Field

[0001] The present invention relates to the technical field of motor drive technology, and in particular to a permanent magnet synchronous drive assembly with a speed change function. Background Art

[0002] Permanent magnet synchronous drive assemblies are highly efficient, high-power-density power systems widely used in electric vehicles, industrial drives, rail transit, and other fields. Their speed-shifting function is achieved through power electronics control technology, offering advantages such as fast dynamic response, high efficiency, and compact size. The permanent magnet synchronous drive assembly with a reducer offers both high efficiency, low losses, and high torque output.

[0003] The permanent magnet synchronous drive assembly consists of a permanent magnet synchronous motor, a speed reducer, an inverter, a controller, a sensor system, and a cooling system. The core components of the permanent magnet synchronous motor are the stator and rotor. Energy conversion is achieved through magnetic field synchronization, driving the rotor's rotation. The inverter converts DC power into variable-frequency, variable-amplitude AC power, controlling the output voltage and frequency through pulse-width modulation technology to adjust the motor speed. The controller, based on a control algorithm, receives sensor signals in real time and adjusts the inverter output parameters. The speed reducer reduces speed and increases torque.

[0004] The variable speed function is possible by controlling the motor's input electrical frequency and voltage amplitude to adjust the synchronous speed of the rotating magnetic field. Based on the speed-frequency formula, the controller adjusts the output frequency through the inverter, directly varying the motor speed. In the field-weakening speed range, the voltage phase angle is adjusted to weaken the magnetic field, enabling constant power operation over a wide speed range. Finally, sensors monitor the rotor position in real time, and the controller dynamically compensates for load fluctuations to ensure that the speed accurately tracks the command value.

[0005] However, permanent magnets are susceptible to irreversible demagnetization at high temperatures or in strong demagnetizing fields, which can affect their lifespan. This is because the magnetism of permanent magnets originates from the oriented arrangement of their internal magnetic domains. When the temperature exceeds a certain threshold, this stable arrangement of magnetic domains is disrupted. The magnetization state of a permanent magnet is described by its hysteresis loop. When a reverse magnetic field is applied, the magnetic flux density decreases along the loop. If the reverse magnetic field strength exceeds the coercive force of the material, the magnetization state passes the loop's "knee" and enters an irreversible phase. At this point, even after removing the reverse magnetic field, the magnet cannot regain its original remanent magnetization. Summary of the Invention

[0006] The present invention aims to solve the above technical problems and provides a permanent magnet synchronous drive assembly with a speed change function.

[0007] The technical solution of the present invention is a permanent magnet synchronous drive assembly with a speed-changing function, comprising a hybrid excitation motor, a reducer, a dual-channel inverter, a controller, and a sensor network;

[0008] The hybrid excitation motor includes a stator and a rotor configured as a fractional slot winding. The rotor is provided with a permanent magnet array, an isolation layer, and an excitation winding array, which are sequentially arranged from the axis outward and also distributed along the axial direction of the rotor. The permanent magnet array is spliced ​​by multiple fan-shaped magnetic steels, and the N poles and S poles are alternately arranged to form a main magnetic field pole pair. The number of excitation windings in the excitation winding array is half the number of magnetic steels, and each winding is embedded between adjacent pole pairs. The axis of the excitation winding is offset at a certain angle from the axis of the permanent magnet pole to form a spatial phase difference. The permanent magnet magnetic circuit formed by the permanent magnet array and the stator and the electric excitation magnetic circuit formed by the excitation winding array and the stator are vectorially superimposed at the air gap.

[0009] The dual-channel inverter includes a main power channel for driving the stator winding and an excitation channel for supplying power to the rotor excitation winding through brushes and slip rings;

[0010] The sensing network includes a current detection unit, a voltage detection unit, an encoder, a fiber grating sensor, and a magnetoresistive sensor. The current detection unit is used to detect the three-phase current output by the inverter, the voltage detection unit is used to detect the DC bus voltage, the encoder is used to detect the position and speed of the rotor, the fiber grating sensor is embedded in the permanent magnet array, and is used to detect the temperature of the magnetic steel. The magnetoresistive sensor is arranged at the air gap and is used to detect the synthetic magnetic field vector.

[0011] As an embodiment, the reducer is a two-stage planetary reducer, the first-stage planetary transmission structure of the reducer is connected to the hybrid excitation motor, and the second-stage planetary transmission structure of the reducer is connected to the load.

[0012] As an embodiment, the isolation layer is wound into a ring shape using nanocrystalline ribbon and is continuously wound along the circumference of the ring in a spiral involute trajectory. Each turn of the ribbon is offset relative to the previous turn, so that multiple turns of the ribbon are superimposed in a stepped offset manner.

[0013] As an embodiment, the strip is sprayed with a magnesium oxide insulation layer after every five layers of winding to form an insulation barrier in a vertical axial direction.

[0014] As an embodiment, the magnetic steel is arranged in sections along the axial direction of the rotor.

[0015] As an implementation method, non-magnetic conductive ribs are provided between adjacent N-pole magnetic steels and S-pole magnetic steels to limit circumferential magnetic leakage.

[0016] As an embodiment, the controller configures the following dynamic control strategy:

[0017] The EKF algorithm estimates the remanent magnetization of the permanent magnet array online based on the input three-phase current, DC bus voltage, rotor position, rotor speed, and magnet temperature, and outputs the current remanent magnetization and remanent magnetization attenuation.

[0018] Dynamically adjust the excitation current output by the excitation channel according to the magnet temperature, current remanence, synthetic magnetic field vector, remanence attenuation, and load requirements;

[0019] When the temperature of the magnetic steel is greater than the temperature safety value, the reverse excitation current is started to weaken the synthetic magnetic field strength, and the amplitude of the excitation current is set according to the critical demagnetization magnetic field strength;

[0020] When the demagnetization magnetic field intensity is greater than the critical demagnetization magnetic field intensity, the reverse excitation current is increased until the demagnetization magnetic field intensity is less than the critical demagnetization magnetic field intensity;

[0021] When the temperature of the magnetic steel is lower than the temperature safety value and the demagnetization magnetic field strength is lower than the critical demagnetization magnetic field strength, the reverse excitation current is turned off;

[0022] When residual magnetism decays or load demand increases, the forward excitation current is increased to enhance the synthetic magnetic field strength;

[0023] The critical demagnetization magnetic field strength is calculated based on the real-time magnetic steel temperature, and the demagnetization magnetic field strength is calculated based on the current remanence and the synthetic magnetic field vector.

[0024] As an implementation method, the priority of using the demagnetization magnetic field intensity alone as an execution condition is higher than the priority of using the magnetic steel temperature alone as an execution condition, and the priority of using the magnetic steel temperature alone as an execution condition is higher than the priority of using other execution conditions.

[0025] In one embodiment, the reducer includes a housing, the first-stage planetary transmission structure and the second-stage planetary transmission structure are built into the housing, the first-stage planetary transmission structure includes a first sun gear, a first planetary gear, a first planetary carrier, and a first inner ring gear; the first sun gear is connected to the hybrid excitation motor, the first inner ring gear is fixed to the housing, and the first planetary gear is mounted on the first planetary carrier and is located between the first sun gear and the first inner ring gear;

[0026] The second-stage planetary transmission structure includes a second sun gear, a second planetary gear, a second planetary carrier and a second inner ring gear; the second sun gear is connected to the first planetary carrier, the second inner ring gear is fixed to the housing, the second planetary gear is mounted on the second planetary carrier and is located between the second sun gear and the second inner ring gear, and the second planetary carrier is used to connect the load.

[0027] As an embodiment, the number of the first planetary gears is set to 4, and the number of the second planetary gears is set to 3.

[0028] Compared to the prior art, the present invention offers the following advantages: This variable-speed permanent magnet synchronous drive assembly overcomes the irreversible demagnetization problem of conventional permanent magnet synchronous drive assemblies at high temperatures or under strong demagnetizing conditions, while also achieving coordinated optimization of magnetic, thermal, and force fields at the system level. This highly reliable variable-speed electric drive system is designed. This variable-speed permanent magnet synchronous drive assembly reconstructs conventional permanent magnet synchronous drive assemblies through a "permanent magnet + auxiliary excitation winding" synergistic excitation structure. While retaining the high efficiency advantages of permanent magnets, it also introduces a dynamically adjustable electromagnetic compensation magnetic field, creating a four-dimensional system-level solution. The motor utilizes a hybrid excitation motor with an innovative rotor topology, resulting in a composite magnetic circuit structure with "axial layering + circumferential staggering." The inverter utilizes a dual-channel inverter, one for the main power channel and one for the excitation channel. The controller uses an extended Kalman filter (EKF) algorithm to estimate the remanent magnetization of the permanent magnet array in real time. The controller optimizes the magnetic field ratio between the permanent magnets and the electric excitation winding based on load demand and magnet temperature feedback. The sensor network includes a current detection unit, a voltage detection unit, an encoder, a fiber Bragg grating (FBG) sensor, and a magnetoresistive sensor. The current detection unit detects the three-phase current output by the inverter, the voltage detection unit detects the DC bus voltage, and the encoder detects the rotor position and speed. The fiber Bragg grating sensor is embedded within the permanent magnet array to detect the magnet temperature, and the magnetoresistive sensor is located in the air gap to detect the resultant magnetic field vector. Furthermore, a speed reducer is incorporated, giving the permanent magnet synchronous drive assembly both the efficient operation provided by power electronics control technology and the high torque output provided by mechanical speed change.

[0029] In summary, the permanent magnet synchronous drive assembly with variable speed function forms the above four-dimensional linkage. On the premise of ensuring the safety of the permanent magnet, it integrates the current residual magnetism, synthetic magnetic field vector and voltage data in real time, dynamically adjusts the excitation current, and realizes efficient and high dynamic response operation of the drive system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a hybrid excitation motor of a permanent magnet synchronous drive assembly with a variable speed function provided in an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of the partial structure of a hybrid excitation motor of a permanent magnet synchronous drive assembly provided in an embodiment of the present invention from a first perspective;

[0032] Figure 3 A schematic diagram of the partial structure of a hybrid excitation motor of a permanent magnet synchronous drive assembly provided in an embodiment of the present invention from a second perspective;

[0033] Figure 4 A system block diagram of a permanent magnet synchronous drive assembly provided in an embodiment of the present invention;

[0034] Figure 5 This is a structural schematic diagram of a two-stage planetary transmission in a reducer provided in an embodiment of the present invention.

[0035] In the figure: 1. Hybrid excitation motor; 2. Stator; 3. Rotor; 4. Permanent magnet array; 5. Isolation layer; 6. Excitation winding array; 7. Magnet; 8. Excitation winding; 9. Non-magnetic ribs; 10. Reducer; 11. Housing; 12. First-stage planetary transmission structure; 13. Second-stage planetary transmission structure; 14. First sun gear; 15. First planetary gear; 16. First planetary carrier; 17. First inner ring gear; 18. Second sun gear; 19. Second planetary gear; 20. Second planetary carrier; 21. Second inner ring gear. DETAILED DESCRIPTION

[0036] The above and other embodiments and advantages of the present invention are clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments.

[0037] In one embodiment, Figures 1 to 4 shown.

[0038] The present embodiment provides a permanent magnet synchronous drive assembly with variable speed function, with a reducer 10, comprising a hybrid excitation motor 1, a dual-channel inverter, a controller, and a sensor network. The hybrid excitation motor 1 comprises a stator 2 configured as a fractional slot winding and a rotor 3. The rotor 3 is provided with a permanent magnet array 4, an isolation layer 5, and an excitation winding array 6, which are sequentially arranged from the axis outward and also distributed along the axial direction of the rotor 3. The permanent magnet array 4 is spliced ​​from multiple fan-shaped magnetic steels 7, and the north and south poles are alternately arranged along the circumference to form the main magnetic field pole pairs. The number of excitation windings 8 in the excitation winding array 6 is half the number of magnetic steels 7, and each winding is embedded between adjacent main magnetic field pole pairs. The axis of the excitation winding 8 is offset at a certain angle from the axis of the permanent magnet pole to form a spatial phase difference. The permanent magnet magnetic circuit formed by the permanent magnet array 4 and the stator 2 and the electric excitation magnetic circuit formed by the excitation winding array 6 and the stator 2 are vectorially superimposed at the air gap. The dual-channel inverter includes a main power channel that drives the stator windings and an excitation channel that supplies power to the rotor excitation winding 8 via brushes and slip rings. The sensing network includes a current detection unit, a voltage detection unit, an encoder, a fiber Bragg grating (FBG) sensor, and a magnetoresistive sensor. The current detection unit detects the three-phase current output by the inverter, the voltage detection unit detects the DC bus voltage, the encoder detects the position and speed of the rotor 3, the fiber Bragg grating (FBG) sensor embedded within the permanent magnet array 4 detects the magnet temperature, and the magnetoresistive sensor, located in the air gap, detects the resultant magnetic field vector. The controller employs the following dynamic control strategy: Using an EKF algorithm, the residual magnetization of the permanent magnet array is estimated online based on the input three-phase current, DC bus voltage, rotor position, rotor speed, and magnet temperature, and the current residual magnetization and residual magnetization attenuation are output. The excitation current output by the excitation channel is dynamically adjusted based on the magnet temperature, current residual magnetization, resultant magnetic field vector, residual magnetization attenuation, and load demand.

[0039] In this embodiment, the permanent magnet synchronous drive assembly with speed change function is designed to overcome the problem of irreversible demagnetization that traditional permanent magnet synchronous drive assemblies are prone to under high temperature or strong demagnetization field, and at the same time achieve coordinated optimization of magnetic field, thermal field and force field at the system level, and is an electric drive system with high reliability speed change function.

[0040] This variable-speed permanent magnet synchronous drive assembly reconstructs the traditional permanent magnet synchronous drive assembly through a "permanent magnet + auxiliary excitation winding" collaborative excitation structure. While retaining the high efficiency advantage of permanent magnets, it introduces a dynamically adjustable electromagnetic compensation magnetic field, forming a four-dimensional linkage system-level solution. This four-dimensional linkage is reflected in improvements to the motor, inverter, controller, and sensor network.

[0041] In terms of the motor, a hybrid excitation motor 1 is used, in which the topology of the rotor 3 is innovated so that the rotor 3 has an "axial layering + circumferential staggered" composite magnetic circuit structure.

[0042] The inner layer of rotor 3 comprises a permanent magnet array 4, which can be a 12-pole V-shaped neodymium iron boron permanent magnet array embedded in slots in high-permeability silicon steel sheets. The outer layer of rotor 3 comprises an excitation winding array 6, which can be a 6-pole distributed copper excitation winding array connected to an external excitation power supply via slip rings and brushes. A magnetic barrier layer, or isolation layer 5, is provided between the inner and outer layers of rotor 3. This isolation layer can be a nanocrystalline alloy isolation ring, positioned between the permanent magnet layer and the excitation layer to achieve magnetic circuit decoupling. The rotor inner layer, magnetic barrier layer, and rotor outer layer are radially layered. Axially, the rotor inner layer is also the bottom axial layer, the magnetic barrier layer is also the middle axial layer, and the rotor outer layer is also the top axial layer. This means that rotor 3 has an "axially layered" magnetic circuit structure.

[0043] Around the circumference of rotor 3, a permanent magnet module is positioned every 60° mechanical angle (corresponding to a 12-pole motor), forming a main magnetic field pole pair with north and south poles. Excitation slots are embedded between adjacent pole pairs, housing field windings 8. The axis of field winding 8 is offset 30° (other mechanical angles are possible) from the axis of the permanent magnet poles to create a spatial phase difference. This gives rotor 3 a "circumferentially staggered" magnetic circuit structure.

[0044] The permanent magnet magnetic circuit follows the path from permanent magnet's north pole to rotor yoke, stator, rotor yoke, and permanent magnet's south pole. The electrical excitation magnetic circuit follows the path from field winding's north pole to magnetic barrier, air gap, stator, air gap, magnetic barrier, and field winding's south pole. These two magnetic circuits are vectorially superimposed at the air gap. By adjusting the direction and amplitude of the excitation current, the following modes can be achieved: magnetization mode (excitation current and permanent magnetic field in the same direction) increases air gap flux density and enhances output torque; field weakening mode (excitation current and permanent magnetic field in opposite directions) broadens the constant power speed regulation range and minimizes permanent magnet demagnetization; and zero excitation mode (excitation current is zero) disables the electrical excitation to reduce losses.

[0045] The inverter utilizes a dual-channel inverter: a main power channel and an excitation channel. The main power channel is a three-phase full-bridge circuit based on thyristors, driving the stator windings. The excitation channel uses an independent H-bridge topology, outputting an adjustable 0-48V DC voltage, which is supplied to the rotor excitation winding 8 via brushes and slip rings.

[0046] The controller uses an extended Kalman filter (EKF) algorithm to estimate the remanent magnetization of the permanent magnet array in real time. This EKF algorithm can predict the gradual decay of remanent magnetization. The controller establishes an exponential relationship between magnet temperature and the critical demagnetization field. By inputting the real-time magnet temperature, the controller calculates the corresponding critical demagnetization field strength based on this exponential relationship. Based on load demand and magnet temperature feedback, the controller optimizes the ratio of the magnetic fields provided by the permanent magnets and the electromagnetic excitation.

[0047] In terms of the sensing network, a current detection unit, a voltage detection unit, an encoder, a fiber Bragg grating sensor, and a magnetoresistive sensor are set up. The current detection unit is used to detect the three-phase current of the inverter output, the voltage detection unit is used to detect the DC bus voltage, the encoder is used to detect the position and speed of the rotor 3, the fiber Bragg grating sensor is embedded in the permanent magnet array 4, and is used to detect the temperature of the magnetic steel. The magnetoresistive sensor is set at the air gap and is used to detect the synthetic magnetic field vector.

[0048] In this embodiment, the permanent magnet synchronous drive assembly with variable speed function forms the above four-dimensional linkage. Under the premise of ensuring the safety of the permanent magnet, it integrates the current residual magnetism and synthetic magnetic field vector in real time, dynamically adjusts the excitation current, and realizes efficient and high dynamic response operation of the drive system.

[0049] In this embodiment, the permanent magnet synchronous drive assembly with a speed change function has a reducer 10 that includes a first planetary gear and a second planetary gear, thereby forming a two-stage planetary transmission structure. At present, based on the two-stage planetary transmission structure and the existing shifting structure, the gear switching function can be mechanically realized. When the two-stage reducers work simultaneously, they output low speed and high torque, which is suitable for load conditions. When only the second-stage reducer works, it outputs high speed and low torque, which is suitable for no-load fast movement. When both the first-stage reducer and the second-stage reducer are not working, the transmission components rotate freely and there is no power output, which is suitable for towing or fault traction.

[0050] In one embodiment, Figure 4 shown.

[0051] This embodiment provides a permanent magnet synchronous drive assembly with variable speed function. The controller dynamically adjusts the excitation current output by the excitation channel based on the magnet temperature, current residual magnetism, synthetic magnetic field vector, residual magnetism attenuation, and load demand. The dynamic control strategy is as follows: when the magnet temperature exceeds the temperature safety value, the reverse excitation current is activated to weaken the synthetic magnetic field strength, and the excitation current amplitude is set according to the critical demagnetization magnetic field strength. When the demagnetization magnetic field strength exceeds the critical demagnetization magnetic field strength, the reverse excitation current is increased until the demagnetization magnetic field strength is less than the critical demagnetization magnetic field strength. When the magnet temperature is less than the temperature safety value and the demagnetization magnetic field strength is less than the critical demagnetization magnetic field strength, the reverse excitation current is turned off. When residual magnetism attenuation occurs or the load demand increases, the forward excitation current is increased to enhance the synthetic magnetic field strength. The critical demagnetization magnetic field strength is calculated based on the real-time magnet temperature, and the demagnetization magnetic field strength is calculated based on the current residual magnetism and synthetic magnetic field vector. The current residual magnetism is obtained from the EKF estimator, and the synthetic magnetic field vector is obtained from the reluctance sensor.

[0052] In this embodiment, when the magnetic steel temperature exceeds the temperature safety value, a reverse excitation current is initiated to weaken the resultant magnetic field strength, and the excitation current amplitude is set based on the critical demagnetization magnetic field strength. This is overtemperature protection, triggered when the magnetic steel temperature exceeds the temperature safety value (which can be 120°C). The response action is to initiate a reverse excitation current to weaken the resultant magnetic field strength. Simultaneously, the critical demagnetization magnetic field strength is calculated based on the exponential relationship between the magnetic steel temperature and the critical demagnetization magnetic field, and the excitation current amplitude is set based on the critical demagnetization magnetic field strength. This also reduces output torque. When the demagnetization magnetic field strength exceeds the critical demagnetization magnetic field strength, the reverse excitation current is increased until the demagnetization magnetic field strength falls below the critical demagnetization magnetic field strength. This is overdemagnetization magnetic field protection, triggered when the demagnetization magnetic field strength exceeds the critical demagnetization magnetic field strength. The response action is to increase the reverse excitation current until the demagnetization magnetic field strength falls below the critical demagnetization magnetic field strength. This also limits the maximum motor speed. When the magnetic steel temperature falls below the temperature safety value and the demagnetization magnetic field strength falls below the critical demagnetization magnetic field strength, the reverse excitation current is shut off. This is efficiency optimization. The trigger conditions are when the magnet temperature is below the safe temperature value and the demagnetization magnetic field strength is below the critical demagnetization magnetic field strength. The response action is to shut down the electric excitation to maximize permanent magnet utilization. At the same time, the inverter modulation strategy can also be adjusted to reduce switching losses. When residual magnetization decays or load demand increases, the forward excitation current is increased to enhance the resultant magnetic field strength and output torque. This is performance optimization.

[0053] In this embodiment, the variable-speed permanent magnet synchronous drive assembly, while ensuring the safety of the permanent magnets, dynamically adjusts the excitation current by integrating the current residual magnetization and the resulting magnetic field vector in real time, achieving efficient and highly dynamic operation of the drive system. Simultaneously, it achieves coordinated optimization of the magnetic, thermal, and force fields at the system level.

[0054] In one embodiment, Figure 4 shown.

[0055] The permanent magnet synchronous drive assembly with a speed change function provided in this embodiment has a higher priority when the demagnetization magnetic field intensity is used as an execution condition than when the magnetic steel temperature is used as an execution condition, and the priority when the magnetic steel temperature is used as an execution condition is higher than when other conditions are used as execution conditions.

[0056] In this embodiment, the priority is demagnetization protection > temperature protection > efficiency optimization, performance optimization. When high temperature and strong demagnetization field occur simultaneously, reverse excitation and power reduction are prioritized.

[0057] In one embodiment, Figure 4 shown.

[0058] The permanent magnet synchronous drive assembly with variable speed function provided in this embodiment includes the following steps for online estimation of the residual magnetization of the permanent magnet array: a prediction step: predicting the current residual magnetization state based on the residual magnetization state at the previous moment and the motor dynamic model; and an update step: revising the predicted value using the real-time measurements of the three-phase current, the rotor speed, and the magnet temperature.

[0059] In this embodiment, the motor has its own dynamic model, involving the state vector, input voltage, and process noise. The EKF algorithm outputs an estimate of the current residual magnetization based on the motor dynamic model. The predicted value can be corrected using the triangular relationship between temperature, magnetic field (rotor speed), and current. Furthermore, when the difference between the magnetic field strength of the current residual magnetization feedback and the magnetic field strength of the synthetic magnetic field vector feedback exceeds a threshold, the correction parameter is adjusted. The current residual magnetization is estimated and corrected by the EKF algorithm, while the synthetic magnetic field vector is detected by the reluctance sensor. The difference between the two is used to correct the correction parameters of the EKF model. The two complement each other, allowing the EKF to predict gradual attenuation, while the reluctance sensor can capture sudden magnetic field distortion. Furthermore, the reluctance sensor's detection also verifies the magnetic field state.

[0060] In one embodiment, Figure 2 and Figure 3 shown.

[0061] The permanent magnet synchronous drive assembly with a speed change function provided in this embodiment has an isolation layer 5 that is wound into a ring shape using nanocrystalline strips and is continuously wound along the circumference of the ring in a spiral involute trajectory. Each turn of the strip is offset relative to the previous turn, so that multiple turns of the strip are superimposed in a stepped offset manner.

[0062] In this embodiment, the isolation layer 5 is wound in a spiral involute trajectory to ensure close contact between layers. Multiple layers of tape are stacked in a stepped offset pattern to maximize interlayer contact area and reduce air gaps and magnetic flux leakage.

[0063] In one embodiment, Figure 2 and Figure 3 shown.

[0064] In the permanent magnet synchronous drive assembly with a speed-changing function provided in this embodiment, a magnesium oxide insulation layer is sprayed on the strip after every five layers of winding to form an insulation barrier perpendicular to the axis.

[0065] In this embodiment, the insulating layer can achieve interlayer insulation, that is, a nano-magnesium oxide insulating layer is sprayed after every five layers are wound to form an insulating barrier in a vertical axial direction to block the interlayer current.

[0066] In one embodiment, Figure 3 shown.

[0067] In the permanent magnet synchronous drive assembly with a speed-changing function provided in this embodiment, the magnets 7 are arranged in sections along the axial direction of the rotor.

[0068] In this embodiment, the magnetic steel 7 is arranged in sections along the axial direction of the rotor, and the length of each section is aligned with the core of the stator 2 to form an independent magnetic circuit module.

[0069] In one embodiment, Figure 3 shown.

[0070] In the permanent magnet synchronous drive assembly with a speed change function provided in this embodiment, non-magnetic conductive ribs 9 are provided between adjacent N-pole magnetic steels 7 and S-pole magnetic steels 7 to limit circumferential magnetic leakage.

[0071] In this embodiment, the non-magnetic ribs 9 can be titanium alloy ribs. Non-magnetic titanium alloy ribs are arranged between each adjacent N-pole magnetic steel 7 and S-pole magnetic steel 7 to limit circumferential magnetic leakage and force the magnetic flux to close along the designed path.

[0072] In one embodiment, Figure 5 shown.

[0073] The permanent magnet synchronous drive assembly with speed change function provided in this embodiment includes a reducer 10 comprising a housing 11 and a first-stage planetary transmission structure 12 and a second-stage planetary transmission structure 13 built into the housing 11. The first-stage planetary transmission structure 12 includes a first sun gear 14, first planetary gears 15, a first planetary carrier 16, and a first inner ring gear 17. The first sun gear 14 is connected to the hybrid excitation motor 1, the first inner ring gear 17 is fixed to the housing 11, and the first planetary gears 15 are mounted on the first planetary carrier 16 and positioned between the first sun gear 14 and the first inner ring gear 17. The second-stage planetary transmission structure 13 includes a second sun gear 18, second planetary gears 19, a second planetary carrier 20, and a second inner ring gear 21. The second sun gear 18 is connected to the first planetary carrier 16, the second inner ring gear 21 is fixed to the housing 11, and the second planetary gears 19 are mounted on the second planetary carrier 20 and positioned between the second sun gear 18 and the second inner ring gear 21. The second planetary carrier 20 is used to connect to an external load. Furthermore, there are four first planetary gears 15 and three second planetary gears 19.

[0074] This embodiment utilizes a differentiated layout of four planetary gears in the first stage and three in the second stage, ensuring a compact design while achieving optimal load distribution between the two stages. The structural design of a fixed double internal gear ring linked to the planetary carrier creates two independent reduction paths, achieving a compound amplification effect on the overall reduction ratio while increasing axial space by only 15%. The unique planetary gear phase staggering arrangement achieves a 90° phase difference in meshing impact forces, reducing vibration and noise.

[0075] The above specific embodiments further illustrate the purpose of the invention, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it is pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A permanent magnet synchronous drive assembly with a speed change function, characterized in that: Includes hybrid excitation motor, reducer, dual-channel inverter, controller, and sensor network; The hybrid excitation motor includes a stator and a rotor configured as a fractional slot winding. The rotor is provided with a permanent magnet array, an isolation layer, and an excitation winding array, which are sequentially arranged from the axis outward and also distributed along the axial direction of the rotor. The permanent magnet array is spliced ​​from multiple fan-shaped magnetic steels, and the north poles and the south poles are alternately arranged to form a main magnetic field pole pair. The number of excitation windings in the excitation winding array is half the number of magnetic steels, and each winding is embedded between adjacent pole pairs. The axis of the excitation winding is offset at a certain angle from the axis of the permanent magnet pole to form a spatial phase difference. The permanent magnet magnetic circuit formed by the permanent magnet array and the stator and the electric excitation magnetic circuit formed by the excitation winding array and the stator are vectorially superimposed at the air gap. The dual-channel inverter includes a main power channel for driving the stator winding and an excitation channel for supplying power to the rotor excitation winding through brushes and slip rings; The sensing network includes a current detection unit, a voltage detection unit, an encoder, a fiber grating sensor, and a magnetoresistive sensor. The current detection unit is used to detect the three-phase current output by the inverter, the voltage detection unit is used to detect the DC bus voltage, the encoder is used to detect the position and speed of the rotor, the fiber grating sensor is embedded in the permanent magnet array, and is used to detect the temperature of the magnetic steel. The magnetoresistive sensor is arranged at the air gap and is used to detect the synthetic magnetic field vector.

2. The permanent magnet synchronous drive assembly with speed change function according to claim 1, characterized in that: The reducer is a two-stage planetary reducer, wherein the first-stage planetary transmission structure of the reducer is connected to the hybrid excitation motor, and the second-stage planetary transmission structure of the reducer is connected to the load.

3. The permanent magnet synchronous drive assembly with speed change function according to claim 1, characterized in that: The isolation layer is wound into a ring shape using nanocrystalline ribbons and is continuously wound along the circumference of the ring in a spiral involute trajectory. Each turn of the ribbon is offset relative to the previous turn, so that multiple turns of the ribbon are superimposed in a stepped offset manner.

4. The permanent magnet synchronous drive assembly with speed change function according to claim 3, characterized in that: After the strip is wound every five layers, a magnesium oxide insulation layer is sprayed to form an insulation barrier perpendicular to the axis.

5. The permanent magnet synchronous drive assembly with speed change function according to claim 1, characterized in that: The magnetic steels are arranged in sections along the axial direction of the rotor.

6. The permanent magnet synchronous drive assembly with speed change function according to claim 1, characterized in that: Non-magnetic conductive ribs are provided between adjacent N-pole magnetic steels and S-pole magnetic steels to limit circumferential magnetic leakage.

7. The permanent magnet synchronous drive assembly with speed change function according to claim 1, characterized in that: The controller is configured with the following dynamic control strategy: The EKF algorithm estimates the remanent magnetization of the permanent magnet array online based on the input three-phase current, DC bus voltage, rotor position, rotor speed, and magnet temperature, and outputs the current remanent magnetization and remanent magnetization attenuation. Dynamically adjust the excitation current output by the excitation channel according to the magnet temperature, current remanence, synthetic magnetic field vector, remanence attenuation, and load requirements; When the temperature of the magnetic steel is greater than the temperature safety value, the reverse excitation current is started to weaken the synthetic magnetic field strength, and the amplitude of the excitation current is set according to the critical demagnetization magnetic field strength; When the demagnetization magnetic field intensity is greater than the critical demagnetization magnetic field intensity, the reverse excitation current is increased until the demagnetization magnetic field intensity is less than the critical demagnetization magnetic field intensity; When the temperature of the magnetic steel is lower than the temperature safety value and the demagnetization magnetic field strength is lower than the critical demagnetization magnetic field strength, the reverse excitation current is turned off; When residual magnetism decays or load demand increases, the forward excitation current is increased to enhance the synthetic magnetic field strength; The critical demagnetization magnetic field strength is calculated based on the real-time magnetic steel temperature, and the demagnetization magnetic field strength is calculated based on the current remanence and the synthetic magnetic field vector.

8. The permanent magnet synchronous drive assembly with speed change function according to claim 7, characterized in that: The priority of using the demagnetization magnetic field intensity as the execution condition is higher than the priority of using the magnetic steel temperature as the execution condition, and the priority of using the magnetic steel temperature as the execution condition is higher than the priority of using other conditions as the execution condition.

9. The permanent magnet synchronous drive assembly with speed change function according to claim 2, characterized in that: The reducer includes a housing, the first-stage planetary transmission structure and the second-stage planetary transmission structure are built into the housing, the first-stage planetary transmission structure includes a first sun gear, a first planetary gear, a first planetary carrier, and a first inner ring gear; the first sun gear is connected to the hybrid excitation motor, the first inner ring gear is fixed to the housing, and the first planetary gear is mounted on the first planetary carrier and is located between the first sun gear and the first inner ring gear; The second-stage planetary transmission structure includes a second sun gear, a second planetary gear, a second planetary carrier and a second inner ring gear; the second sun gear is connected to the first planetary carrier, the second inner ring gear is fixed to the housing, the second planetary gear is mounted on the second planetary carrier and is located between the second sun gear and the second inner ring gear, and the second planetary carrier is used to connect the load.

10. The permanent magnet synchronous drive assembly with speed change function according to claim 9, characterized in that: The number of the first planetary gears is set to four, and the number of the second planetary gears is set to three.

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