Torque fluctuation suppression method and system for electrically excited doubly salient motor based on multiple mcus

Abstract

The application discloses a torque fluctuation suppression method of an electrically excited doubly salient motor based on multiple MCUs, and comprises the following steps: armature winding pre-segmentation and parameter calibration; multiple slave MCU initialization and synchronous calibration; out-of-phase current reference generation and distribution; independent high-speed current closed-loop control of each armature branch; reluctance torque dynamic optimization and fault tolerance management; and the application also provides a torque fluctuation suppression system of an electrically excited doubly salient motor based on multiple MCUs. The application breaks through the torque pulsation bottleneck of a traditional electrically excited doubly salient motor from the system architecture level, significantly reduces the torque pulsation under all working conditions, improves the utilization rate of the reluctance torque and the comprehensive torque density, simultaneously constructs a modular distributed control architecture, enhances the system reliability and power scalability, realizes the fault-tolerant operation of the driving module, avoids the system shutdown caused by single-point failure, and supports the flexible expansion of the power level without the need of redesigning the motor body and the main power topology through the construction of the modular architecture.

Description

Technical Field

[0001] This invention relates to the field of motor torque ripple suppression technology, and in particular to a method and system for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs. Background Technology

[0002] As a new type of stator-excited motor, the electrically excited doubly salient pole motor adopts a doubly salient pole structure for its stator and rotor. The rotor is made of only stacked silicon steel sheets, without permanent magnets or winding structures. It has outstanding advantages such as simple structure, low manufacturing cost, excellent heat dissipation performance, and controllable excitation. It can achieve wide-range speed regulation and constant power operation by adjusting the excitation current, and has broad application prospects in high-reliability application scenarios such as aerospace, industrial transmission, and high-power speed regulation drive.

[0003] Currently, research on torque ripple suppression in electrically excited doubly salient pole motors mainly focuses on two directions: electromagnetic structure optimization and advanced control algorithm compensation. Electromagnetic structure optimization methods often employ structural improvements such as increasing the pole arc coefficient, stator skew, and rotor skew. Control algorithms primarily include harmonic injection and model predictive torque control. However, due to the nonlinear characteristics of the motor's magnetic circuit, stator slotting effect, and armature commutation characteristics, the motor's air gap magnetic field contains abundant high-order harmonics, resulting in significant commutation torque ripple during operation. Traditional solutions struggle to achieve ideal suppression effects. Conventional structural optimization methods not only have limited torque ripple suppression efficiency but also sacrifice the motor's effective output torque, leading to a decrease in torque density. Advanced algorithms such as model predictive control involve large computational loads, high dependence on sensor accuracy, and poor real-time performance, making them insufficiently adaptable to low-speed, heavy-load, and high-speed dynamic conditions, thus limiting their torque ripple suppression effectiveness.

[0004] In high-power drive scenarios, the industry commonly uses multi-winding parallel connection to improve the motor's current carrying capacity and output power. However, the traditional parallel winding architecture can only achieve simple current shunting and cannot perform precise phase coordination control of the current in each parallel branch. Due to the differences in impedance and back electromotive force parameters among the armature branches, internal circulating currents are easily generated during parallel operation. This not only significantly increases system operating losses but also causes the torque pulsations of each branch to superimpose, further worsening the overall torque fluctuation of the motor and ultimately seriously affecting the motor's operating stability and control accuracy.

[0005] Meanwhile, existing drive control systems mostly adopt a centralized single-controller architecture, where all current closed-loop calculations, torque calculations, and harmonic compensation algorithms are performed by a single controller. This results in a concentrated computational load and limited control bandwidth, making it difficult to adapt to the high-speed dynamic operating conditions of motors. Furthermore, the traditional system architecture is highly rigid, requiring a redesign of the motor's electromagnetic structure and main power topology for power level expansion, leading to poor system scalability and high iteration costs. More critically, centralized control and traditional parallel winding architectures lack fault tolerance and branch reconfiguration capabilities. Failure of a single power branch, controller, or communication link can easily cause the entire machine to shut down, making it difficult for the system's operational reliability to meet the high reliability and uninterrupted operation requirements of high-end equipment.

[0006] In summary, existing electrically excited doubly salient pole motor drive technology suffers from numerous problems, including poor torque ripple suppression, low torque density, weak adaptability to high-speed conditions, and poor system scalability. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for suppressing torque fluctuations in an electrically excited doubly salient pole motor based on multiple MCUs, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs, comprising the following steps:

[0009] Step S1, Armature winding pre-segmentation and parameter calibration: The centralized armature winding of each phase of the motor stator is divided into equal number of turns, and the single winding is split into N independent armature branches, N≥2. Then, each armature branch is tested and calibrated. Then, one end of all armature branches is connected to the motor neutral point and the other end is connected to the power conversion unit.

[0010] Step S2, Multi-slave MCU initialization and synchronous calibration: Configure an independent slave MCU for each armature branch. All slave MCUs are connected to the master MCU. Then the master MCU sends a synchronous clock calibration command to all slave MCUs. Subsequently, each slave MCU completes the calibration of the current sensor and the reading of the rotor position sensor data for its own branch, and establishes the initial parameters for the closed-loop control of the current in its own branch.

[0011] Step S3, generation and distribution of phase-shifted current reference: The main control MCU calculates the rated current amplitude of a single armature branch according to the total torque command, and then calculates the phase offset and current reference value of each armature branch.

[0012] Step S4, independent high-speed current closed-loop control of each armature branch: real-time acquisition of the actual phase current of this armature branch and the rotor position feedback of this cycle, completion of closed-loop calculation, output of PWM drive signal to control the full-bridge power converter corresponding to this armature branch, and during the calculation process, improved quasi-PR harmonic compensation is superimposed on the PI control.

[0013] Step S5: Dynamic optimization of reluctance torque and fault tolerance management. Each slave MCU adjusts the current trigger angle of its branch in real time to keep the phase difference between the armature reaction magnetic field and the excitation magnetic field in the optimal range. When any armature branch or slave MCU fails, the phase offset and current reference value of the remaining N-1 normal armature branches are recalculated, and the power reduction fault tolerance operation mode is automatically entered.

[0014] Further optimization involves the following steps: in step S1, the armature branch test and calibration are performed using an impedance analyzer for DC resistance testing and winding inductance testing. The impedance between the armature branches is controlled by fine-tuning the lead wire length, and the impedance deviation is no greater than 1%.

[0015] In a further optimization, all slave MCUs in step S2 are connected to the master MCU via a high-speed synchronous bus. The clock synchronization error adopts a bus-distributed clock synchronization mechanism, and the clock synchronization error of each slave MCU is no greater than 1μs.

[0016] Further optimization involves the initial parameters in step S2 including the PI controller proportional coefficient, the PI controller integral coefficient, and the preset value of the phase shift angle.

[0017] Further optimization, the phase offset in step S3 The calculation is based on the total number of branches N and the dominant harmonic frequency of torque pulsation, and the calculation formula is as follows:

[0018] ,

[0019] in, The dominant harmonic frequency for torque pulsation.

[0020] Further optimization is achieved by using the following formula to calculate the current reference value in step S3:

[0021] ,

[0022] in, For the first Reference current values ​​for each branch (k=1,2,…,N). This represents the amplitude of the current in a single branch. Given the current electric angular velocity of the motor, the main control MCU will input the corresponding phase offset. The current reference value is sent to each slave MCU in real time via the synchronous bus, and the instruction refresh cycle does not exceed 100μs.

[0023] Further optimization involves using an improved incremental PI algorithm for closed-loop calculation in step S4, with the calculation process entirely executed locally by the slave MCU. The master MCU does not participate in the underlying current loop calculation but only monitors the operating status of each slave MCU via the bus.

[0024] Further optimization is needed, and the faults in step S5 include overcurrent, overtemperature, and communication faults.

[0025] Further optimization, the phase offset in step S5 The recalculation formula is:

[0026] .

[0027] The present invention also provides a torque ripple suppression system for an electrically excited doubly salient pole motor based on multiple MCUs, for implementing the torque ripple suppression method for an electrically excited doubly salient pole motor based on multiple MCUs described above, comprising: a motor body, a multi-MCU distributed control unit, and an independent power conversion unit;

[0028] The motor body includes a stator, a rotor, an excitation winding, an armature winding, and a divided armature branch.

[0029] The multi-MCU distributed control unit adopts a master-slave hierarchical distributed multi-MCU control architecture, which includes a master control MCU and slave control MCUs;

[0030] The power conversion unit includes multiple independent full-bridge power converters, each of which is connected to an armature branch.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) Breaking through the torque ripple bottleneck of traditional electrically excited doubly salient pole motors at the system architecture level, without changing the electromagnetic structure of the stator and rotor of the motor body, significantly reducing torque ripple under all operating conditions, improving reluctance torque utilization and comprehensive torque density, while constructing a modular distributed control architecture to enhance system reliability and power scalability, realize fault-tolerant operation of drive modules, and avoid system shutdown due to single point of failure; and by constructing a modular architecture, it supports flexible expansion of power level without redesigning the motor body and main power topology;

[0033] (2) By canceling out multiple phase-shifted harmonics, the synthetic torque ripple rate is reduced from more than 30% to less than 5%, vibration and noise are greatly suppressed, and torque ripple is significantly reduced; the utilization rate of reluctance torque is enhanced by independent high-speed current regulation, and higher torque is output under the same volume and current, with torque density increased by 10% to 15%.

[0034] (3) When any slave MCU or armature branch fails, the master MCU automatically isolates the faulty unit, while the remaining armature branches continue to operate. The system only reduces power output without interrupting operation, achieving high reliability and fault tolerance, and meeting the requirements of high reliability scenarios such as aerospace.

[0035] (4) Different power levels can be adapted by adding or subtracting the N value of the armature branch. There is no need to change the stator and rotor structure of the motor body, nor is it necessary to redesign the main controller and main power topology. Only by adding the slave control MCU and power conversion unit on the corresponding armature branch can the power expansion main power topology be completed, supporting rapid product iteration and forming a modular and scalable architecture.

[0036] (5) The distributed parallel architecture can distribute the underlying current closed-loop calculation to each slave MCU, greatly reducing the computational load of a single controller, improving the current loop response bandwidth, adapting to high-speed dynamic conditions, suppressing the effect without being limited by the speed range, maintaining a stable torque ripple suppression effect under all operating conditions, and enhancing the real-time control performance. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the torque ripple suppression method for an electrically excited doubly salient pole motor based on multiple MCUs disclosed in this invention.

[0038] Figure 2 This is a schematic diagram of the overall framework of the multi-MCU-based electrically excited doubly salient pole motor torque ripple suppression system disclosed in this invention. Detailed Implementation

[0039] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0040] Example 1

[0041] like Figure 1 As shown, this application discloses a method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs, including the following steps:

[0042] Step S1, Armature Winding Pre-segmentation and Parameter Calibration: First, the centralized armature winding of each phase of the motor stator is divided into equal turns, splitting a single winding into N independent armature branches, where N≥2, to ensure that the total number of conductor turns, wire diameter specifications, and slot space distribution of each armature branch are completely consistent, reducing the initial parameter deviation between branches; then, each armature branch is tested and calibrated, including testing and calibrating the DC resistance and winding inductance of the armature branch, and the impedance deviation between armature branches is controlled within 1% by fine-tuning the lead-out length; then, one end of all armature branches is connected to the motor neutral point to form a common Y-type connection, and the other end is led out through independent lead-out terminals and connected to the power conversion unit to achieve electrical isolation between branches;

[0043] Step S2, Multi-slave MCU initialization and synchronization calibration: Configure an independent slave MCU for each armature branch. All slave MCUs are connected to the master MCU through a high-speed synchronization bus. After power-on, the master MCU sends a synchronization clock calibration command to all slave MCUs. Based on the bus distributed clock synchronization mechanism, the clock synchronization error of each slave MCU is controlled within 1μs to ensure phase control accuracy. Subsequently, each slave MCU completes the calibration of the current sensor and the reading of rotor position sensor data for its own branch, establishes the initial parameters of the current closed-loop control for its own branch, including the PI controller proportional coefficient, PI controller integral coefficient and phase offset angle preset value, and completes system initialization.

[0044] Step S3, generation and distribution of phase-shifted current reference: The main control MCU calculates the rated current amplitude of a single armature branch based on the total torque command issued by the host computer, combined with the current excitation current and motor parameters. Then, based on the total number of armature branches N and the dominant harmonic frequency of torque pulsation, it calculates the phase offset and current reference value of each armature branch.

[0045] Step S4, Independent High-Speed ​​Current Closed-Loop Control for Each Armature Branch: After receiving the current reference value with a preset offset, each slave MCU collects the actual phase current of its armature branch and the rotor position feedback for the current cycle in real time. It uses an improved incremental PI algorithm to complete the closed-loop calculation and outputs a PWM drive signal to control the independent full-bridge power converter corresponding to its armature branch. The calculation process is entirely executed locally by the slave MCU. The master MCU does not participate in the underlying current loop calculation and only monitors the operating status of each slave MCU through the bus. For the phase current harmonic components caused by back EMF harmonics, an improved quasi-PR harmonic compensation stage is superimposed on the PI control to further suppress the harmonics corresponding to the 3rd and 6th main torque pulsations in the phase current, thereby reducing the torque pulsation components of a single branch.

[0046] Step S5: Dynamic optimization of reluctance torque and fault-tolerant management. Each slave MCU adjusts the current firing angle of its branch in real time according to the current rotor position and speed, so that the phase difference between the armature reaction magnetic field and the excitation magnetic field is always kept in the optimal range, ensuring that the reluctance torque and the excitation torque are positively superimposed throughout the entire electrical cycle. When any armature branch or slave MCU experiences an overcurrent, overtemperature, or communication fault, the slave MCU automatically reports to the master MCU. The master MCU immediately issues a fault isolation command, cuts off the power output of the faulty branch, recalculates the phase offset and current reference value of the remaining N-1 normal armature branches, and updates the phase offset of each armature branch after adjustment. The system automatically enters the power reduction fault-tolerant operation mode without the need for shutdown maintenance.

[0047] In this embodiment, by canceling out multiple phase-shifted harmonics, the combined torque ripple rate is reduced from the traditional >30% to less than 5%, significantly suppressing vibration and noise, and achieving a significant reduction in torque ripple. By sequentially shifting the fundamental phase of the phase current output by each independent slave MCU according to 1 / N of the dominant harmonic period of the torque ripple, the torque ripple components generated by each armature branch form a fixed phase shift in the time domain. The dominant harmonic components cancel out in the combined torque, achieving torque ripple suppression at the system level without altering the motor's structure. Based on the acquired rotor position signal, each slave MCU adjusts the current firing angle of its branch in real time, ensuring that the phase difference between the armature reaction magnetic field and the excitation magnetic field remains within the optimal range. This guarantees that the reluctance torque and excitation torque are positively superimposed throughout the entire electrical cycle, improving the reluctance torque utilization rate, increasing the total output torque, and outputting higher torque with the same volume and current, increasing torque density by 10%-15%. When any slave MCU or armature branch fails, the master MCU automatically isolates the faulty unit, while the remaining armature branches continue to operate. The system only reduces power output without interrupting operation, meeting the high reliability requirements of aerospace and other applications. Different power levels can be adapted by increasing or decreasing the armature branch N value (N≥2), without changing the motor's stator and rotor structure or redesigning the master MCU and main power topology. Power expansion of the main power topology can be achieved simply by adding corresponding armature branch slave MCUs and power conversion units, supporting rapid product iteration. The master-slave hierarchical distributed multi-MCU control architecture formed by the master and slave MCUs distributes the underlying current closed-loop calculation to each slave MCU, significantly reducing the computational load on a single controller, improving the current loop response bandwidth, adapting to high-speed dynamic conditions, and maintaining stable torque ripple suppression across all operating conditions, regardless of speed range.

[0048] In this embodiment, in step S1, the armature winding is divided to achieve a parallel structure of multiple armature branches, thus enabling the reconfiguration of the armature winding. In step S2, a master-slave hierarchical architecture is used, consisting of a master MCU and slave MCUs. The master MCU receives the total torque command from the host computer, performs total power calculation, phase offset allocation, system status monitoring, and fault coordination. It does not participate in the underlying current closed-loop calculation but only sends current reference values ​​and synchronization commands to each slave MCU. Each armature branch is configured with an independent slave MCU. Each slave MCU independently collects the phase current and rotor position feedback signals of its branch, independently performs high-speed current closed-loop calculation and PWM drive signal generation. All slave MCUs communicate with the master MCU through a high-speed synchronization bus (CAN FD or EtherCAT) to achieve clock synchronization and command transmission.

[0049] In this embodiment, the initial parameters include the PI controller proportional coefficient, integral coefficient, and a preset value for the phase misalignment angle. The PI controller proportional coefficient is used to quickly eliminate dynamic errors; the larger the error, the greater the adjustment force, which can improve the system response speed. The PI controller integral coefficient is used to eliminate steady-state error, ensuring stable operation without fixed deviation over a long period of time; as long as a steady-state error exists, the integral term will continue to accumulate and output until the error returns to zero. The preset value for the phase misalignment angle is used to compensate for encoder installation zero-point deviation, sampling delay, and drive timing offset, correct the motor detection electrical angle, achieve complete decoupling of the d / q axes, correct the rotor phase reference, and ensure normal decoupling of motor vector control and stable torque.

[0050] In this embodiment, the phase offset The calculation is based on the total number of branches N and the dominant harmonic frequency of torque pulsation, and the calculation formula is as follows:

[0051] ,

[0052] in, The dominant harmonic frequency for torque pulsation is the frequency of a complete electrical cycle. The arc is evenly distributed to N parallel branches, and the current in each branch is staggered and in equal phase.

[0053] In this embodiment, after the phases of the multiple armature branch currents are evenly staggered, the pulsating torques of each armature branch cancel each other out, the output torque is smooth, the pulsation of the synthesized total output torque is greatly reduced, and the motor vibration, noise and current harmonics are reduced simultaneously, thereby achieving the purpose of suppressing torque pulsation.

[0054] In this embodiment, the formula for calculating the current reference value is:

[0055] ,

[0056] in, For the first Branch roads ( The current reference values ​​for (=1,2,…,N) are given. Number the branch roads This represents the amplitude of the current in a single branch. Given the current electric angular velocity of the motor, the main control MCU will input the corresponding phase offset. The current reference value is sent to each slave MCU in real time via the synchronous bus, and the instruction refresh cycle does not exceed 100μs to ensure the real-time performance of phase control.

[0057] In this embodiment, This describes how the master MCU sends a current reference to the k-th slave MCU, and the slave MCU's internal current loop PI tracks this waveform. The master MCU distributes current reference values ​​to each channel via a high-speed synchronous bus, with a refresh period of ≤100μs. This ensures strict phase synchronization and no timing deviation in the multiple armature branches, preventing distortion of the offset angle due to communication delays. The high-speed command refresh within 100μs ensures high phase offset accuracy for each armature branch, stable cancellation effect, and real-time synchronization. The uniform phase shift of the multiple armature branch currents causes their respective harmonic torques to cancel each other out, resulting in a significant reduction in motor vibration, noise, and current harmonics.

[0058] In this embodiment, overcurrent faults include output armature phase overcurrent, DC bus side overcurrent, switch transistor shoot-through short circuit, and ground / phase-to-phase short circuit overcurrent; overtemperature faults include overheating of power device temperature, power circuit bus / copper busbar temperature, slave MCU onboard chip temperature, and branch motor winding temperature; communication faults include command reception loss, bus hardware layer fault, synchronization timing out-of-sync fault, data verification error, and slave control uplink reporting fault. When any type of fault is triggered, the slave MCU latches the fault type, fault occurrence time, and fault parameters, and uploads the fault identifier to the master MCU in real time via the high-speed synchronization bus. After receiving the fault report, the master MCU issues a fault isolation command, disconnects the faulty armature branch, and prevents the fault from spreading to other parallel branches.

[0059] In this embodiment, the phase offset The recalculation formula is:

[0060] ,

[0061] That is, when any armature branch experiences overcurrent, overtemperature, or communication faults, and the faulty armature branch is disconnected or isolated, only N-1 effective armature branches remain to participate in torque ripple cancellation. Therefore, it is necessary to completely eliminate the faulty armature branches. The radians are redistributed evenly to the remaining branches, and the phase difference is updated.

[0062] Example 2

[0063] This application also discloses a torque ripple suppression system for an electrically excited doubly salient pole motor based on multiple MCUs, used to implement the aforementioned torque ripple suppression method for an electrically excited doubly salient pole motor based on multiple MCUs. The system includes: a motor body, a multi-MCU distributed control unit, and an independent power conversion unit. The motor body is the controlled execution object, the multi-MCU distributed control unit is the control core of the system, and the power conversion unit is the power execution layer.

[0064] The stator, rotor, field winding, and armature winding of the motor body constitute the basic topology of an electrically excited doubly salient pole motor. The field winding provides a constant excitation magnetic field, and the armature winding outputs electromagnetic torque. The segmented armature branches enable independent drive of multiple branches, providing a hardware foundation for subsequent multi-converter, multi-slave distributed architectures. Each armature branch can output armature current with phase shift by an independent power conversion unit. Harmonic torques from multiple branches cancel each other out, suppressing overall torque fluctuations at the source. When a single branch fails, it can be isolated and disconnected, while the remaining branches continue to operate at derating without requiring a complete shutdown.

[0065] The multi-MCU distributed control unit adopts a master-slave hierarchical distributed multi-MCU control architecture, including a master MCU and slave MCUs. The master MCU, or master controller, is used for upper-level overall planning and global computation scheduling. The slave MCU, or slave controller, is used for lower-level branch closed-loop control. Each armature branch is equipped with an independent slave MCU for local closed-loop control. The slave MCU has a built-in PI controller to complete d / q axis current closed-loop tracking; it also uses a superimposed phase offset angle correction to ensure accurate d / q axis decoupling. The master and slave MCUs communicate via a high-speed synchronous bus, with an instruction refresh cycle ≤100μs to ensure real-time phase accuracy.

[0066] The power conversion unit contains multiple independent full-bridge power converters. Each full-bridge power converter is connected to an armature branch. That is, a full-bridge power converter uniquely corresponds to a split armature branch and a slave MCU. The branch hardware is completely decoupled and can receive the PWM drive signal from the slave MCU to complete the DC to AC power conversion and output armature current with a specified phase to supply the corresponding armature branch.

[0067] In this implementation, the torque fluctuation suppression principle of the torque fluctuation suppression system for the electrically excited doubly salient pole motor is as follows: the main control MCU evenly distributes the torque fluctuation. The electrical angle is applied to all branches, and the armature currents of each armature branch are uniformly staggered by a fixed phase. The torque harmonics generated by each branch cancel each other out, significantly reducing the overall torque ripple. The slave MCU independently completes the current PI closed loop locally, and the master NCU only sends the current reference, distributing the control computing power. A single armature branch control failure does not affect the whole system. When an armature branch experiences overcurrent, overtemperature, or communication failure, the faulty branch is isolated and disconnected. The master MCU recalculates the phase offset and single-path current amplitude of the remaining armature branches, continuously suppressing torque ripple. The system does not shut down with reduced torque, but only operates at a reduced rating.

[0068] Example 3

[0069] like Figure 2 As shown, in this embodiment, the motor body structure adopts a 12 / 8 pole structure, that is, 12 slots in the stator and 8 poles in the rotor. Both the excitation winding and the armature winding adopt a concentrated winding structure. Both the stator and the rotor are made of silicon steel sheets stacked together. The rotor has no windings and permanent magnets.

[0070] Armature winding segmentation is achieved as follows: Taking the A-phase armature winding as an example, the original A-phase centralized armature winding is evenly divided into N=3 independent armature branches. Each armature branch has 12 turns and a wire diameter of 1.5mm². The space within the slots is symmetrically distributed. After segmentation, an impedance analyzer is used for calibration. Finally, the impedance deviation of the three armature branches is controlled within 0.8%. One end of the three armature branches is connected to the motor neutral point, and the other end is led out to three independent power interfaces respectively. The B-phase and C-phase are similarly segmented to form a three-branch parallel structure.

[0071] The control architecture is implemented using a hierarchical distributed structure: the main control MCU adopts the high-performance STM32H7 series MCU0, which is responsible for total torque calculation, phase allocation, and fault management; each of the three A-phase armature branches is configured with an independent STM32F4 series slave control MCU1, MCU2, and MCU3, and each slave control MCU1, MCU2, and MCU3 collects the phase currents IA1, IA2, and IA3 and rotor position signals of the corresponding branch; all slave control MCU1, MCU2, and MCU3 are connected to the main control MCU0 via CAN FD, and the main control MCU0 sends current reference signals with preset phase offsets to each slave control MCU1, MCU2, and MCU3, with a communication period of 100μs; each branch is configured with an independent full-bridge power converter, which is independently driven by the corresponding slave control MCU1, MCU2, and MCU3 to realize closed-loop current control of this branch.

[0072] Phase shift control is implemented as follows: In this embodiment, each phase armature winding branch has N=3, therefore the fundamental phases of the currents in the three branches are shifted sequentially. =360º / 3=120º, which corresponds to the 3rd harmonic being dominated by torque pulsation. This perfectly cancels out the dominant harmonic, maximizing the suppression of the synthesized torque pulsation.

[0073] In this embodiment, the complete operation process of the torque fluctuation suppression system for the electrically excited doubly salient pole motor is as follows:

[0074] (1) Initialization phase: After the motor is powered on, the main control MCU0 first completes the system self-test and sends the synchronization clock calibration command to the three armature branches slave control MCU1, MCU2 and MCU3 to calibrate the clock synchronization error of the three nodes to within 0.5μs; then the parameters of the three armature branches of phase A are checked to confirm that the impedance deviation of the three armature branches is less than 0.8%, which meets the design requirements; finally, the rated current amplitude of a single branch is calculated to be 15A based on the current rated torque of the motor, and the preset phase offset is 120°, thus completing the initialization.

[0075] (2) Normal operation phase: The host computer sends a running command with a total torque of 120 N•m to the main control MCU0. The current motor speed is 1500 rpm. The main control MCU0 calculates the total current reference value as 45 A. After equalization, the current amplitude of each armature branch is 15 A. The current reference values ​​of the three A-phase armature branches are as follows:

[0076] ,

[0077] ,

[0078] ,

[0079] The main control MCU0 will use the above current reference value The data is sent to three armature branches via CAN FD – slave MCU1, MCU2, and MCU3. Each slave MCU1, MCU2, and MCU3 collects the actual current of its branch in real time at a frequency of 10kHz. Combined with the rotor position signal, high-speed closed-loop control is completed, and the corresponding full-bridge power converter is independently driven to output current to the three armature windings.

[0080] Because the fundamental phases of the three currents are staggered by 120°, the dominant third harmonic components of the torque pulsation are also staggered by 120°. The three pulsating torques cancel each other out during synthesis, and the pulsating component of the final synthesized torque is only less than 1 / 10 of that of a single branch. The torque pulsation rate is reduced from 32% in the traditional scheme to 4.2%, showing a significant suppression effect. At the same time, each slave MCU dynamically adjusts the current trigger angle according to the current rotor position, matching the current phase with the rotor d / q axis angle, which increases the reluctance torque ratio from 12% in the traditional scheme to 21%, and the total output torque is increased by 12%, achieving an effective improvement in torque density.

[0081] (3) Fault-tolerant operation phase: When an overcurrent fault occurs in the second armature branch, the slave controllers MCU1, MCU2, and MCU3 corresponding to the armature branch immediately report the fault information to the master controller MCU0. The master controller MCU0 issues a fault isolation command within 2ms, shuts down the output of the second full-bridge converter, and at the same time recalculates the phase offset of the remaining two normal branches, adjusts the offset to 180°, and updates the current reference values ​​of the two armature branches. They are respectively:

[0082] ,

[0083] ,

[0084] After the update, the torque ripple of the remaining two armature branches can still be effectively canceled, with the torque ripple rate only rising to 6.8%. The system maintains 80% of the rated torque output and will not experience a complete shutdown, meeting the requirements of high reliability applications.

[0085] (4) Power expansion stage: If the rated power of the motor needs to be increased from 100kW to 150kW, it is only necessary to increase the number of armature branch divisions per phase from N=3 to N=4, and add a corresponding slave MCU and an independent full-bridge power converter. There is no need to change the stator and rotor structure of the motor body, nor is it necessary to replace the master control MCU0. The expansion can be completed by modifying the branch parameters in the master control MCU0. The expansion cycle is shortened from 3 months in the traditional scheme to 1 week, realizing modular rapid expansion.

[0086] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs, characterized in that, Includes the following steps: Step S1, Armature winding pre-segmentation and parameter calibration: The centralized armature winding of each phase of the motor stator is divided into equal number of turns, and the single winding is split into N independent armature branches, N≥2. Then, each armature branch is tested and calibrated. Then, one end of all armature branches is connected to the motor neutral point and the other end is connected to the power conversion unit. Step S2, Multi-slave MCU initialization and synchronous calibration: Configure an independent slave MCU for each armature branch. All slave MCUs are connected to the master MCU. Then the master MCU sends a synchronous clock calibration command to all slave MCUs. Subsequently, each slave MCU completes the calibration of the current sensor and the reading of the rotor position sensor data for its own branch, and establishes the initial parameters for the closed-loop control of the current in its own branch. Step S3, generation and distribution of phase-shifted current reference: The main control MCU calculates the rated current amplitude of a single armature branch according to the total torque command, and then calculates the phase offset and current reference value of each armature branch. Step S4, independent high-speed current closed-loop control of each armature branch: real-time acquisition of the actual phase current of this armature branch and the rotor position feedback of this cycle, completion of closed-loop calculation, output of PWM drive signal to control the full-bridge power converter corresponding to this armature branch, and during the calculation process, improved quasi-PR harmonic compensation is superimposed on the PI control. Step S5: Dynamic optimization of reluctance torque and fault tolerance management. Each slave MCU adjusts the current trigger angle of its branch in real time to keep the phase difference between the armature reaction magnetic field and the excitation magnetic field in the optimal range. When any armature branch or slave MCU fails, the phase offset and current reference value of the remaining N-1 normal armature branches are recalculated, and the power reduction fault tolerance operation mode is automatically entered.

2. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, In step S1, the armature branch test and calibration is performed by DC resistance test and winding inductance test using an impedance analyzer. The impedance between the armature branches is controlled by fine-tuning the lead wire length, and the impedance deviation is no greater than 1%.

3. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, In step S2, all slave MCUs are connected to the master MCU via a high-speed synchronous bus. The clock synchronization error adopts a bus-distributed clock synchronization mechanism, and the clock synchronization error of each slave MCU is no greater than 1μs.

4. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, The initial parameters in step S2 include the PI controller proportional coefficient, the PI controller integral coefficient, and the preset value of the phase shift angle.

5. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, Phase offset in step S3 The calculation is based on the total number of branches N and the dominant harmonic frequency of torque pulsation, and the calculation formula is as follows: , in, The dominant harmonic frequency for torque pulsation.

6. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, The formula for calculating the current reference value in step S3 is as follows: ， in, For the first Reference current values ​​for each branch (k=1,2,…,N). This represents the amplitude of the current in a single branch. Given the current electric angular velocity of the motor, the main control MCU will input the corresponding phase offset. The current reference value is sent to each slave MCU in real time via the synchronous bus, and the instruction refresh cycle does not exceed 100μs.

7. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, In step S4, the closed-loop calculation adopts an improved incremental PI algorithm and the calculation process is entirely executed locally by the slave MCU. The master MCU does not participate in the underlying current loop calculation, but only monitors the operating status of each slave MCU through the bus.

8. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, The faults in step S5 include overcurrent, overtemperature, and communication faults.

9. The method for suppressing torque ripple in an electrically excited doubly salient pole motor based on multiple MCUs according to claim 1, characterized in that, Phase offset in step S5 The recalculation formula is: 。 10. A torque ripple suppression system for an electrically excited doubly salient pole motor based on multiple MCUs, characterized in that, The method for suppressing torque fluctuations in an electrically excited doubly salient pole motor based on multiple MCUs as described in any one of claims 1 to 9 includes: a motor body, a multi-MCU distributed control unit, and an independent power conversion unit; The motor body includes a stator, a rotor, an excitation winding, an armature winding, and a divided armature branch. The multi-MCU distributed control unit adopts a master-slave hierarchical distributed multi-MCU control architecture, which includes a master control MCU and slave control MCUs; The power conversion unit includes multiple independent full-bridge power converters, each of which is connected to an armature branch.

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