Decoupling type multi-phase motor based on two-phase multiple and phase number

Abstract

The invention discloses a decoupling type multi-phase motor based on a two-phase multiple phase number, and solves the technical problems of complex winding coupling and control, limited fault tolerance and high hardware cost of a traditional multi-phase motor based on a multiple phase number of 3. The motor adopts a multiple of 2 as a phase number, a stator winding is spatially orthogonally / symmetrically distributed and is designed without a neutral point, and natural decoupling of a magnetic field is realized; each phase is provided with an independent H-bridge control unit, adjacent phases adopt bridge arm sharing topological optimization, and the main controller can adjust the current of each phase through simple PI control; a fault phase can be directly isolated when a fault occurs, and a healthy phase can continue to work without complex reconstruction; the method has the advantages of high control precision, high fault tolerance and low hardware cost, is adaptive to asynchronous, permanent magnet synchronous, reluctance and other motor types, and can be applied to the fields of new energy automobiles, industrial driving, aerospace and the like.

Description

Technical Field

[0001] This invention relates to the field of electrical drive technology, and in particular to a decoupled multiphase motor based on a two-phase multiple phase number. Background Technology

[0002] In modern industrial and civilian sectors, electric motors, as core equipment for energy conversion and power output, directly affect the efficiency, stability, and control precision of various mechanical systems. Multiphase motors, due to their significant advantages in power density, fault tolerance, and harmonic suppression, are widely used in high-end fields such as new energy vehicles, rail transportation, industrial drives, and aerospace.

[0003] Currently, mainstream multiphase motor designs are based on traditional three-phase motors and are extended. The number of phases is usually a multiple of 3, such as 6-phase, 9-phase, 12-phase, etc. This design relies on the mature theoretical system and industrial application foundation of three-phase motors. By increasing the number of phases, power is distributed and the current stress of each phase is reduced, which improves the motor's operating performance to a certain extent. At the same time, it has a certain fault tolerance capability. In the event of a fault, it can continue to operate through the remaining healthy phases, avoiding the significant losses caused by the sudden shutdown of the system.

[0004] However, multiphase motors with a phase number that is a multiple of 3 have many inherent limitations: First, the winding structure and magnetic field distribution continue the coupling characteristics of three-phase motors, making it difficult to completely eliminate inter-phase electromagnetic coupling. Dynamic response is prone to cross-coupling, requiring complex coordinate transformations and decoupling algorithms to achieve precise control, increasing the computational burden on the controller and raising the difficulty of algorithm implementation, which is not conducive to application in low-cost embedded systems. Second, the common neutral point connection method of multiple windings is usually adopted. The common-mode voltage spike at the neutral point will cause serious electromagnetic interference, and when one phase fails, the fault current can easily be conducted to other phases through the neutral point, interfering with the operation of healthy phases and increasing the difficulty of fault isolation. Third, the control topology of multiple sets of three-phase inverters working together is often adopted. The synchronization and coordination of each set of inverters further increases the control difficulty and the topology lacks flexibility.

[0005] At the same time, the design of multiphase motors with a number of phases that are not multiples of 3 has not received sufficient attention, especially the research on motors with a number of phases that are multiples of 2 (4-phase, 8-phase, 10-phase, 14-phase, 16-phase, etc.) is still in the exploratory stage, and there is a lack of mature winding design and control schemes.

[0006] In summary, the shortcomings of existing multiphase motors with a phase number that is a multiple of 3 in terms of structural coupling, control complexity, and topology flexibility make it difficult to meet the demands of modern industry for efficient, precise, and simple motor control. Exploring a multiphase motor design that is free from the limitations of three-phase expansion, has natural decoupling characteristics, and is easy to control has become an urgent technical problem to be solved in this field. Summary of the Invention

[0007] This application provides a decoupled multiphase motor based on a two-phase multiple phase number, which solves the technical problems of winding coupling, complex control, limited fault tolerance, high hardware cost, and insufficient topology flexibility of traditional three-phase multiple phase multiphase motors. It achieves natural decoupling of the motor's magnetic field and simple control, while retaining and improving the fault tolerance and operating efficiency of the multiphase motor, reducing hardware costs, and expanding the motor's adaptability and application scenarios.

[0008] This application proposes a decoupled multiphase motor based on a two-phase multiple of the number of phases. The number of phases of the motor is a positive integer multiple of 2, and it includes a stator, a rotor, and a control system. The stator is provided with several phase windings, and each phase winding has no neutral point electrical connection. The windings are spatially orthogonal or symmetrically distributed to achieve natural magnetic field decoupling. The control system includes a main controller and an H-bridge drive module corresponding to each winding. The main controller does not require complex coordinate transformation and decoupling algorithms and can independently adjust the current of each phase winding.

[0009] Preferably, the number of phases of the motor is 4, 8 or 16; when it is 4 phases, the windings are divided into four phases A, B, C and D, with phases A and C, and phases B and D symmetrically distributed at 180 degrees, and the spatial angle between adjacent phase windings is 90 degrees; when it is 8 phases, the spatial angle between each phase winding is 45 degrees.

[0010] Preferably, the rotor adopts an asynchronous squirrel cage, reluctance, or permanent magnet synchronous structure; when it is a permanent magnet synchronous structure, the permanent magnet can be made of materials such as neodymium iron boron, samarium cobalt, or ferrite, and can be installed in a surface-mount or built-in manner. Surface-mount is suitable for high-speed scenarios, while built-in is suitable for scenarios with high saliency ratio requirements. The number of rotor pole pairs matches the number of stator phases.

[0011] Preferably, the H-bridge drive module adopts a topology design in which adjacent phase bridge arms are shared, which reduces the number of power switching transistors and lowers hardware costs and circuit volume; in a 4-phase motor, phase A and phase B, and phase C and phase D each share a set of bridge arms, and in an 8-phase motor, adjacent phases share a set of bridge arms in sequence.

[0012] Preferably, the A-phase H-bridge of the 4-phase motor consists of an independent A-phase bridge arm and a shared A / B-phase bridge arm, and the B-phase H-bridge consists of an independent B-phase bridge arm and a shared A / B-phase bridge arm. The main controller achieves the switching of the shared bridge arm through logic timing control to ensure that the current control of adjacent phases does not conflict with each other.

[0013] Preferably, the motor has inherent fault tolerance. When a phase winding or the corresponding H-bridge drive module fails, the main controller directly cuts off the control signal of the faulty phase, and the remaining healthy phase windings and H-bridge drive modules can continue to work normally without the need for complex reconfiguration of the control strategy.

[0014] Preferably, the motor is compatible with asynchronous motors, permanent magnet synchronous motors, and reluctance motors, and the drive control of different types of motors can be achieved by adjusting the current frequency, amplitude, or energizing sequence of each phase winding.

[0015] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. Natural magnetic field decoupling significantly improves control accuracy and dynamic response: Based on the orthogonal structure of two-phase 90-degree vertical windings, multi-phase expansion is carried out. The windings of each phase are orthogonally or symmetrically distributed in space, realizing complete magnetic field decoupling and eliminating inter-phase electromagnetic interference. There is no need for complex coordinate transformation and decoupling algorithms. The main controller can independently adjust the current of each phase through simple PI control. The speed response time of dynamic speed regulation of the 4-phase motor is shortened by more than 20% compared with the 6-phase motor of the same power, which greatly improves the applicability of the motor in precision drive scenarios.

[0016] 2. Significantly enhanced fault tolerance and improved system reliability: The independent wiring design without a neutral point limits the fault current to the faulty phase circuit. The independent H-bridge control, combined with the shared topology of the bridge arms, allows the faulty phase to be quickly and directly isolated, and the remaining healthy phases can continue to work without complex reconfiguration. The 8-phase motor can still output more than 75% of its rated power when two phases fail simultaneously, which is far superior to the power output capability of the traditional 12-phase motor under the same fault conditions, meeting the stringent reliability requirements of fields such as new energy vehicles and aerospace.

[0017] 3. Shared bridge arm topology optimization reduces hardware cost and system size: The design of adjacent phase H-bridges sharing a set of bridge arms can reduce the number of power switches by 25% to 30% while ensuring independent control of each phase; the number of power switches in a 4-phase motor is reduced from 16 in the traditional design to 12, reducing hardware cost by about 20%; an 8-phase motor can reduce 8 sets of bridge arms, reducing the system size by more than 30%, balancing performance and economy, which is conducive to the popularization of multiphase motors in low- and mid-end industrial drive fields.

[0018] 4. Wide range of applicability and compatibility with various motor types: The design of this invention is not limited to a specific motor type. It can be applied to asynchronous motors to achieve speed control by adjusting the current frequency and amplitude; it can also be adapted to permanent magnet synchronous motors to achieve high-efficiency output by utilizing the interaction between the magnetic field of the permanent magnet and the orthogonal magnetic field of the stator; it can also be used in reluctance motors to drive the rotor to rotate by controlling the energizing sequence and utilizing the principle of minimum reluctance. This breaks the limitations of traditional multiphase motor design on motor types and expands the application scenarios.

[0019] 5. Neutral point-free design optimizes overall motor performance: Eliminating the traditional neutral point design not only avoids harmonic amplification caused by neutral point potential shift, but also eliminates electromagnetic interference caused by neutral point common-mode voltage spikes, further reducing vibration and noise during motor operation and improving the overall stability and efficiency of motor operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the winding layout of the four-phase motor in this application, showing the spatial distribution relationship of the four-phase windings A, B, C, and D on the stator core, and demonstrating the independent wiring structure without a neutral point; Figure 2 This is a block diagram of the 4-phase motor control system of this application, showing the connection relationship between the main controller, 4 half-bridge drive modules, 1 common bridge arm module and the motor windings; Figure 3 The diagram shows the shared topology of the bridge arms in this application (taking phases A and B as an example), illustrating the composition and connection of the independent bridge arms and shared bridge arms of phases A and B, and demonstrating the design concept of sharing bridge arms between adjacent phases. Figure 4 This is a schematic diagram of the fault-tolerant operation of the 4-phase motor in this application. Detailed Implementation

[0021] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0022] This embodiment takes a 4-phase permanent magnet synchronous decoupled multiphase motor as an example to explain the specific implementation of the present invention in detail. Motors with other multiples of 2, such as 8-phase, 16-phase, etc., as well as asynchronous and reluctance motors, can be extended and designed with reference to the principle of this embodiment.

[0023] I. Overall Structure Design of the Motor like Figure 1 As shown, the 4-phase decoupled multiphase motor in this embodiment mainly consists of a stator, rotor, end cover, bearings, and cooling system. The stator and rotor are the core functional components, which directly determine the electromagnetic performance of the motor. The end cover and bearings support and rotate the rotor. The cooling system is selected from air cooling or water cooling according to the power requirements of the motor to reduce the temperature rise during motor operation.

[0024] 1. Stator Structure The stator core is made of laminated silicon steel sheets, which effectively reduces iron loss. The inner circle of the core has 16 slots evenly distributed (the number of slots can be adjusted according to the motor power and speed range, and must meet the symmetrical distribution requirements of each phase winding) for embedding the four-phase windings A, B, C, and D.

[0025] The windings adopt distributed winding (centralized winding can be selected for high-speed motors to reduce end leakage inductance), and the spatial layout strictly follows the 90-degree orthogonal principle: the spatial angle between the axis of phase A winding and the axis of phase B winding is 90 degrees, and the spatial angles between phase B and phase C, phase C and phase D, and phase D and phase A are all 90 degrees; at the same time, phase A and phase C are symmetrically distributed at 180 degrees, and phase B and phase D are symmetrically distributed at 180 degrees, forming two sets of orthogonal 2-phase winding units (AB phase unit, CD phase unit), ensuring that the magnetomotive force generated by each phase winding is not coupled in space, and realizing natural decoupling of the magnetic field.

[0026] There is no electrical connection between all windings, and an independent wiring method without a neutral point is adopted. The two output terminals of each phase winding are directly connected to the corresponding H-bridge drive module to ensure that the current path of each phase winding is completely independent.

[0027] 2. Rotor Structure In this embodiment, the rotor adopts a permanent magnet synchronous design, and the permanent magnet is made of high-performance neodymium iron boron material to improve magnetic flux density and motor operating efficiency. The permanent magnet is installed in a built-in manner (for high-speed scenarios, surface mounting can be used, which simplifies the installation process), which is suitable for high saliency requirements and improves reluctance torque.

[0028] The number of rotor pole pairs matches the number of stator phases. In this embodiment, the number of pole pairs is 2 (4 poles), which forms a corresponding electromagnetic relationship with the 4-phase windings, ensuring that the rotating magnetic field generated by the stator operates synchronously with the rotor poles, thereby realizing the torque output of the motor.

[0029] For asynchronous motors, a squirrel-cage rotor can be used; for reluctance motors, a salient-pole reluctance rotor can be used, and neither requires any changes to the core design of the stator windings and control system.

[0030] II. Control System Design The 4-phase motor control system in this embodiment consists of a main controller, an H-bridge drive module, a current detection module, a position sensor, and a power supply module. These modules work together to achieve precise and simple control of the motor. The overall structure is as follows: Figure 2 As shown.

[0031] 1. Main Controller A digital signal processor (DSP) can be used as the main controller. If higher control timing requirements are needed, a field-programmable gate array (FPGA) can be used. The core function of the main controller is to receive external speed / torque control commands, combine the real-time current signal from the current detection module with the rotor position / speed signal from the position sensor, generate PWM control signals for each phase H-bridge drive module, and coordinate the logic timing of the shared bridge arm.

[0032] Because the magnetic fields of each phase of the motor are naturally decoupled, the main controller does not require complex coordinate transformations and decoupling algorithms. It can achieve precise closed-loop control of the motor's output torque and speed simply by adjusting the current of each phase through a simple proportional-integral (PI) regulator. For example, when it is necessary to increase the motor speed, the main controller increases the current commands of phases A, B, C, and D proportionally, and adjusts the current amplitude of each phase winding through the H-bridge drive module, so that the speed of the stator rotating magnetic field increases synchronously.

[0033] 2. H-bridge driver module (bridge arm shared topology optimization) To address the issues of high hardware cost and complex structure resulting from the independent configuration of four bridge arms per phase in traditional H-bridge control, this invention optimizes the H-bridge topology by using a shared bridge arm design. Adjacent phases of the H-bridge share a single set of bridge arms, as detailed below. Figure 3 As shown (taking phases A and B as an example).

[0034] In this embodiment, phase A and phase B share a set of bridge arms (VT5, VT6), and phase C and phase D share another set of bridge arms (VT7, VT8). (1) The A-phase H bridge consists of independent bridge arms (VT1, VT2) + shared bridge arms (VT5, VT6); (2) Phase B H bridge consists of independent bridge arms (VT3, VT4) + shared bridge arms (VT5, VT6); (3) The composition of the H bridge in phases C and D is the same as that in phases A and B.

[0035] The main controller uses logic timing control to switch the shared bridge arms, ensuring that the current control of adjacent phases does not conflict. For example, when phase A is conducting, phase B is in a cut-off or reverse control state. When controlling the current of phase A, VT5 and VT6 act as the lower / upper bridge arms of the phase A H-bridge, working with VT1 and VT2 to adjust the direction and amplitude of the phase A current. When controlling the current of phase B, VT5 and VT6 switch to the corresponding bridge arms of the phase B H-bridge, working with VT3 and VT4 to adjust the phase B current.

[0036] While retaining the independent control characteristics of each phase, this design reduces the number of power switches in a 4-phase motor from the traditional 16 to 12, a reduction of 25%, effectively lowering hardware costs and circuit size, without affecting the motor's decoupling characteristics and fault tolerance—when a phase arm fails, only that phase needs to be isolated, and the shared arm can continue to provide support to adjacent phases.

[0037] The H-bridge drive module of this invention adopts a PWM vector modulation scheme: a voltage vector diagram is drawn according to the switching state of the bridge arm, and the required voltage vector is obtained through vector synthesis, thereby determining the PWM duty cycle of each bridge arm and realizing precise adjustment of the current of each phase.

[0038] 3. Current detection module A Hall current sensor is connected in series at the output of each phase H-bridge as a current detection module. It detects the current value of each phase winding in real time and converts the detection signal into an electrical signal to feed back to the main controller. This provides current feedback basis for the PI closed-loop control of the main controller, ensuring that the current of each phase is accurately adjusted according to the command.

[0039] 4. Position sensor A rotary transformer is installed on the motor shaft as a position sensor (an encoder can be used if higher detection accuracy is required) to detect the initial position, real-time position and speed of the rotor in real time. This provides a phase reference for the main controller to generate PWM control signals, ensuring that the energizing sequence of each phase winding is accurately matched with the rotor position, avoiding the stator rotating magnetic field from losing synchronization with the rotor magnetic poles, and ensuring the stable operation of the motor.

[0040] 5. Power Module To provide a stable DC power supply for the control system (main controller, sensors) and H-bridge drive module, a suitable switching power supply is selected according to the motor power and control requirements to ensure the stability of the power supply voltage and current and avoid the impact of power supply fluctuations on the motor control accuracy and operational stability.

[0041] III. Motor Working Process The normal operating procedure of the 4-phase decoupled multiphase motor in this embodiment is as follows. The fault-tolerant operating procedure is a simplified adjustment of the normal operating procedure, while the core steps remain unchanged: 1. Power supply and initialization: The power supply module supplies power to the entire control system and the H-bridge drive module. The main controller completes system initialization and receives speed / torque control commands from the outside. 2. Initial position detection: The position sensor detects the initial position of the rotor and feeds the signal back to the main controller. The main controller determines the initial energizing sequence of the four-phase windings A, B, C, and D based on the initial position signal. 3. Control signal generation: The main controller calculates the target value of the current in each phase based on the external speed / torque command, combined with the real-time current signal from the current detection module and the rotor position / speed signal from the position sensor. It then generates the PWM control signal for each phase H-bridge through the PI regulator, and simultaneously completes the logic timing coordination of the shared bridge arm. 4. Current regulation: The H-bridge drive module controls the conduction and cutoff of each phase switch tube according to the PWM control signal of the main controller, realizes the timing switching of the common bridge arm, and then adjusts the current direction and amplitude of each phase winding. The stator winding generates a synchronous rotating magnetic field, drives the rotor to rotate and realize torque and speed output. 5. Closed-loop feedback regulation: The current detection module and position sensor continuously collect the current signals of each phase and the rotor position / speed signals, and feed them back to the main controller in real time. The main controller dynamically adjusts the PWM control signal according to the feedback signal to realize closed-loop control of motor torque and speed, ensuring that the motor runs stably according to external commands; 6. Fault-tolerant operation (in case of failure): If the current detection module detects an overcurrent or fault in a certain phase, the main controller immediately cuts off the corresponding path between the independent bridge arm and the shared bridge arm of that phase, realizing the rapid isolation of the faulty phase. The remaining three phase windings continue to work normally through their respective H-bridge drive modules without the need to reconfigure the control strategy, ensuring stable output torque of the motor.

[0042] IV. Extended Design of 8-Phase Motor The design principle of the 8-phase decoupled multiphase motor is completely the same as that of the 4-phase motor in this embodiment, with only the number of phases, winding layout, and number of bridge arms being expanded. The core decoupling design, shared bridge arm topology, and simplified control logic remain unchanged. 1. Winding layout: The 8-phase windings are evenly distributed on the stator core at a spatial angle of 45 degrees. Adjacent phases are orthogonal at 45 degrees, achieving natural decoupling of the magnetic field. The independent wiring method without a neutral point is also adopted. 2. Control Topology: The topology adopts a shared bridge arm for two adjacent phases, requiring a total of 6 shared bridge arms + 8 independent bridge arms, which reduces the number of bridge arms by 8 compared to the traditional fully independent H-bridge design, significantly reducing hardware costs. 3. Control System: The timing coordination logic of the extended PWM output channel and the shared bridge arm of the main controller still achieves independent adjustment of the current of each phase through simple PI control, without the need to add a decoupling algorithm; 4. Fault tolerance: The fault tolerance of the 8-phase motor has been further improved. Even if two phases fail at the same time, the remaining 6 phases can still output more than 75% of the rated power, making it suitable for applications with extremely high reliability requirements such as aerospace.

[0043] Industrial applicability Figure 4 This diagram illustrates the fault-tolerant operation of the four-phase motor described in this application. It compares the winding current distribution under normal operation with that under a single-phase fault, demonstrating the magnetic field superposition effect of the remaining three windings and visually showcasing the fault-tolerant performance advantages of this invention. This invention, based on a decoupled multiphase motor with a two-phase multiple number of phases, achieves the technical effects of natural magnetic field decoupling, simplified control logic, improved fault tolerance, and reduced hardware costs. It can be mass-produced and is compatible with various motor types, including asynchronous, permanent magnet synchronous, and reluctance motors. It can be widely applied in new energy vehicles, industrial drives, aerospace, precision machinery, and other fields, possessing significant industrial practicality and market application value.

[0044] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made to the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention. Although preferred embodiments of the present invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A decoupled multiphase motor based on a two-phase multiple phase number, characterized in that, The number of phases of the motor is a positive integer multiple of 2, and includes a stator, a rotor, and a control system. The stator is provided with several phase windings, and each phase winding has no neutral point electrical connection. They are spatially orthogonal or symmetrically distributed to achieve natural magnetic field decoupling. The control system includes a main controller and an H-bridge drive module corresponding to each winding. The main controller does not require complex coordinate transformation and decoupling algorithms and can independently adjust the current of each phase winding.

2. The decoupled multiphase motor based on a two-phase multiple phase number according to claim 1, characterized in that, The motor has 4, 8, or 16 phases. When it has 4 phases, the windings are divided into four phases: A, B, C, and D. Phases A and C, and B and D are symmetrically distributed at 180 degrees, and the spatial angle between adjacent phase windings is 90 degrees. When it has 8 phases, the spatial angle between each phase winding is 45 degrees.

3. The decoupled multiphase motor based on a two-phase multiple phase number according to claim 1, characterized in that, The rotor adopts an asynchronous squirrel cage, reluctance, or permanent magnet synchronous structure. When it is a permanent magnet synchronous structure, the permanent magnet can be made of materials such as neodymium iron boron, samarium cobalt, or ferrite. It can be installed by surface mounting or internal mounting. Surface mounting is suitable for high-speed scenarios, while internal mounting is suitable for scenarios with high saliency requirements. The number of rotor pole pairs matches the number of stator phases.

4. The decoupled multiphase motor based on a two-phase multiple phase number according to claim 1, characterized in that, The H-bridge drive module adopts a topology design that shares bridge arms between adjacent phases, reducing the number of power switching transistors and lowering hardware costs and circuit size; in a 4-phase motor, phases A and B, and phases C and D each share a set of bridge arms, while in an 8-phase motor, adjacent phases share a set of bridge arms in sequence.

5. The decoupled multiphase motor based on a two-phase multiple phase number according to claim 4, characterized in that, The A-phase H-bridge of the 4-phase motor consists of an independent A-phase bridge arm and a shared A / B-phase bridge arm, while the B-phase H-bridge consists of an independent B-phase bridge arm and a shared A / B-phase bridge arm. The main controller achieves the switching of the shared bridge arm through logic timing control, ensuring that the current control of adjacent phases does not conflict with each other.

6. The decoupled multiphase motor based on a two-phase multiple phase number according to claim 1, characterized in that, The motor has inherent fault tolerance. When a phase winding or the corresponding H-bridge drive module fails, the main controller directly cuts off the control signal of the faulty phase, and the remaining healthy phase windings and H-bridge drive modules can continue to work normally without the need for complex reconfiguration of the control strategy.

7. The decoupled multiphase motor based on a two-phase multiple phase number as described in any one of claims 1-6, characterized in that, The motor is compatible with asynchronous motors, permanent magnet synchronous motors and reluctance motors. By adjusting the current frequency, amplitude or energizing sequence of each phase winding, different types of motors can be driven and controlled.

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