416 results about "Torque ripple" patented technology

The invention discloses an open-phase self-fault-tolerant control method for a phase-shift-free dual three-phase permanent magnet synchronous motor. The method can automatically adjust a current distribution relation in the case of an open-phase fault and suppress torque pulsation in combination with neutral point voltage compensation. Comprising the following steps: driving two pairs of three-phase winding modules of the phase-shift-free DTP-PMSM in parallel by adopting two two-level three-phase voltage source inverters, and providing a mathematical model of the motor; current distribution is automatically adjusted; compensating the voltage of the neutral point, and calculating the offset of the fault module; the current is redistributed to suppress the torque ripple after the fault, and the secondary oblique wave component generated by the phase failure fault is eliminated; a current loop controller is improved through dead-beat predictive control; the speed ring controller is optimally designed into an improved sliding mode controller; an improved double-loop controller system is formed by combining improved sliding mode control and dead-beat prediction control, high-gain parameters are set to improve the dynamic response performance of the system, and a new self-fault-tolerant control system is formed.

The invention discloses an embedded motor torque ripple real-time compensation system based on deep learning, and relates to the technical field of motor control and artificial intelligence crossing, the system comprises a hardware data acquisition module, a signal feature extraction module, a deep learning compensation model module, an embedded real-time compensation module and a compensation effect verification module; a motor position and a current signal are acquired in real time through the hardware data acquisition module, dynamic analysis and multi-dimensional feature construction are performed on torque ripple related features by combining the signal feature extraction module, and the deep learning compensation model module learns a fluctuation rule in historical data by using a space-time sequence model to generate a high-precision compensation current. The model adapts to an embedded environment through lightweight design, real-time deployment and dynamic optimization of a compensation algorithm are achieved, compared with traditional PID control, the scheme can adapt to changes of motor operation conditions, the influence of torque fluctuation on system stability is reduced, and the smoothness and efficiency of motor operation are improved.

The invention discloses a stator double-permanent-magnet flux reverse motor, and belongs to the technical field of motors. The motor comprises a stator, a rotor, tangential permanent magnets, Halbach array permanent magnets and windings, the stator is of a double-salient-pole structure formed by combining T-shaped stator iron core blocks. The rotor and the stator are coaxially assembled, and an air gap is reserved between the rotor and the stator. The tangential permanent magnets are installed between the stator iron core blocks and magnetized in the tangential direction, and the adjacent directions are opposite. The Halbach permanent magnets are arranged at the openings of the stator slots, so that the Halbach permanent magnets have a magnetism gathering effect and can provide relatively high air gap flux density; the winding adopts a double-layer centralized design and is embedded into a stator slot; the tangential permanent magnets and the Halbach permanent magnets form a parallel magnetic circuit, and the air gap flux density and the torque density are improved through magnetic field superposition; the number of winding pole pairs meets a specific formula, and the motor structure can be optimized through a finite element method. Compared with a traditional motor, the motor has higher air gap flux density, no-load back electromotive force and torque, lower torque pulsation and a higher power factor, and the electromagnetic performance and the operation stability are remarkably improved.

The invention relates to an anti-interference speed control method for a permanent magnet synchronous motor, in particular to the technical field of electrical engineering, and effectively solves the problem that the control performance of the permanent magnet synchronous motor is degraded due to model parameter drift and external load sudden change under complex working conditions. According to the method, the high robustness of sliding mode control and the rolling optimization characteristic of model prediction control are creatively fused, and an adaptive observer is introduced to estimate the system state and lumped disturbance online, so that the real-time feedforward compensation and active suppression of parameter uncertainty and disturbance are realized; according to the method, the dynamic response speed and the steady-state precision of the system are remarkably improved, the rotating speed fluctuation and the torque ripple are effectively inhibited, meanwhile, controller parameters are adaptively adjusted through an intelligent learning mechanism, the stability and the adaptability in long-term operation are ensured, and the method is suitable for large-scale popularization and application. The limitation that a traditional control strategy depends on an accurate model and the disturbance boundary is unknown is overcome fundamentally, and high-performance and high-robustness speed control is achieved.

The invention relates to the technical field of motor control, discloses a direct current brushless motor control method and system based on current prediction, and aims to solve the problems of large torque ripple, low efficiency and poor stability caused by current loop lag in the prior art. The method comprises the following steps: acquiring a motor operation state signal in real time; determining a sector and an electrical angular velocity based on the rotor position and the rotational speed; inputting related parameters into the mixed current prediction model to obtain a three-phase current prediction value of the next period; a prediction error is calculated in combination with a current instruction, and an optimal voltage vector enabling a cost function to be minimum is solved through a model prediction control algorithm; and finally, a space vector pulse width modulation signal is generated to drive an inverter. According to the method, advanced control is realized by fusing a physical model and a data-driven prediction mechanism, the torque ripple is remarkably reduced, and the energy efficiency and robustness are improved.

The invention relates to the technical field of motor control, and particularly provides a control method and system suitable for a one-way running motor of a two-wheeled electric vehicle. The method aims to solve the problems of unstable motor operation and insufficient reliability caused by torque pulsation in the prior art. The method comprises the following steps: executing off-line identification of motor parameters to obtain initialized parameters; multi-source operation state signals are collected, and a vehicle working condition judgment result is obtained through fusion analysis; performing fault diagnosis and grading evaluation to form a fault-tolerant instruction; dynamic dead zone compensation and self-adaptive overmodulation are implemented by combining the parameters and the working conditions, and an optimization control instruction is output; generating a PWM driving signal through space vector modulation; and responding to the fault-tolerant instruction, and fusing a sensorless algorithm and a health sensor signal to realize degraded operation. According to the invention, the smoothness and efficiency of motor operation and the fault-tolerant capability of the system are effectively improved.

The invention relates to the field of motor structure design and optimization, and discloses a cogging torque and torque ripple optimization method for a permanent magnet motor for a vehicle. The method comprises the steps that based on an electromagnetic scheme, a geometric boundary and a term dictionary, a parameterized geometric prototype containing four symmetric semi-arc auxiliary grooves is constructed, and a design variable set structure is generated; converting the structure into a target evaluation interface structure containing a target item and a constraint item; an improved adaptive particle swarm algorithm is combined with finite element rapid check and a new iteration function to carry out optimization solution, and an updated candidate group structure is generated; and finally, optimal parameters are screened through Pareto sorting and robustness recheck, and an engineering configuration structure is generated. According to the method, through systematic parameter modeling, an efficient collaborative optimization algorithm and simulation evaluation, the optimization efficiency and reliability are remarkably improved, the cogging torque and the torque ripple of the motor are effectively reduced, and meanwhile, the process feasibility and the performance robustness of a design scheme are ensured.

A torque ripple reduction method for a synchronous electric motor of a vehicle includes obtaining, by a control system, look-up tables (LUTs) that each include harmonic currents that satisfy a constrained objective function for phase current magnitude for the synchronous electric motor, based on a requested motor torque, determining, by the control system and using the LUTs, a plurality of currents including fundamental direct and quadrature currents and 6th order and 12th order harmonic quadrature currents, determining, by the control system, direct and quadrature voltages for the synchronous electric motor based on the plurality of currents including injection of the 6th and 12th order harmonic quadrature currents, and controlling, by the control system, the synchronous electric motor based on the determined direct and quadrature voltages to at least one of reduce torque ripples and increase efficiency of the synchronous electric motor.

The invention discloses a motor adaptive harmonic suppression system and method fused with LSTM prediction, and belongs to the technical field of power electronic control. Comprising a harmonic feature extraction module, a trapezoidal angle prediction module, an integral adjustment module and a trapezoidal voltage compensation module. The harmonic feature extraction module converts the three-phase current into dq-axis current; the trapezoidal angle prediction module establishes a model for predicting an optimal initial trapezoidal angle based on a long short-term memory neural network according to the d-axis harmonic current, the motor rotating speed and the bus voltage; the integral adjusting module adjusts a trapezoidal angle on line by inputting a harmonic error; and the trapezoidal voltage compensation module is used for modulating trapezoidal compensation voltage and outputting compensation voltage required by an alpha axis and compensation voltage required by a beta axis. According to the invention, prediction of the long-short-term memory neural network and online adjustment of the trapezoidal angle and modulation of the trapezoidal compensation voltage of the integrator are fused, the harmonic current of the permanent synchronous motor control system can be effectively inhibited, the torque ripple of the motor is reduced, and the performance of the motor is improved.

The invention discloses a current prediction control method and device for a permanent magnet motor, and the method achieves the real-time prediction of a voltage error caused by a dead zone and other non-ideal factors through the powerful nonlinear fitting capability of a feedforward neural network in combination with the learning of historical current time sequence characteristics. And the prediction error is further fed forward and compensated to a future current prediction model to improve the accuracy of current prediction, so that the cost function evaluation is more accurate, the optimal voltage vector is selected, and the steady-state current error and the low-speed torque ripple are effectively inhibited. In this way, precise control over the current of the motor is achieved, and the control precision and operation stability of the driving system are comprehensively improved.

The invention discloses a permanent magnet synchronous motor model prediction control method based on multi-target Pareto optimum, which comprises the following steps: measuring two-phase current, motor rotating speed and rotor position of a permanent magnet synchronous motor, converting the two-phase current into d-axis current and q-axis current according to the rotor position, and converting an alternative voltage vector of an inverter into d-axis voltage and q-axis voltage at the same time; inputting the d-axis current, the q-axis current, the d-axis voltage, the q-axis voltage and the rotating speed of the motor into a current prediction model of the permanent magnet synchronous motor, and predicting a future current state value; establishing a multi-target optimization model including torque ripple, current total harmonic distortion, switching frequency and power loss, calculating by using a multi-target particle swarm algorithm in combination with non-dominated sorting and congestion distance to obtain a Pareto optimal solution set, obtaining an optimal weight factor, and automatically adjusting target weights according to motor operation states under different operation conditions; and constructing a cost function based on the optimal weight factor, and selecting a voltage vector enabling the cost function to be minimum as optimal control output.

The invention provides a rotor punching sheet, a rotor iron core, a rotor, a motor and an air conditioner, the rotor punching sheet is provided with more than two magnetic pole forming areas corresponding to rotor magnetic poles, and each magnetic pole forming area is internally provided with a magnetic steel groove which is arranged on a q axis and extends along the radial direction; the rotor punching sheet is provided with a first magnetic barrier groove located on the d axis between every two adjacent magnetic steel grooves. Wherein first magnetic bridges are formed between the first magnetic barrier grooves and the adjacent magnetic steel grooves on the two sides, and the width of each first magnetic bridge is gradually increased in the radial outward direction of the rotor punching sheet. According to the technical scheme of the invention, the magnetic lines of force can be gradually drawn close to the d axis from the two sides of the d axis, and the sinusoidal property of the magnetic flux in the air gap is better, so that the torque pulsation of the tangential motor can be reduced.

The invention discloses a model prediction control method for a low-common-mode-voltage dual three-phase motor with improved steady-state performance, and belongs to the technical field of dual three-phase permanent magnet synchronous motor control. The method comprises the following steps: firstly, suppressing harmonic current by synthesizing virtual voltage vectors with a specific duty ratio, and synthesizing a candidate output voltage vector by using two adjacent virtual voltage vectors according to a predefined duty ratio; designing a value function without a weight coefficient to select an optimal voltage vector; designing a dual duty ratio technology to calculate the duty ratios of the two virtual voltage vectors for synthesizing the optimal voltage vector; a specific switching sequence in which virtual zero vectors are arranged on two sides and in the middle of a control period is designed, and the switching sequence is generated by using a phase-shifting carrier method. According to the invention, the common-mode voltage can be effectively reduced without adding any hardware circuit, the current harmonic wave and the torque ripple are obviously reduced by expanding the modulation range, the steady-state performance of the system is improved, and the method is suitable for a dual three-phase motor driving system with high requirements on performance and reliability.

The purpose of the present invention is to provide: a rotor for a rotary electric machine, the rotor being capable of reducing torque ripple while suppressing a decrease in maximum torque; and a rotary electric machine. This rotor 3 comprises a rotor core 31 having: magnets; magnet insertion holes into which the magnets are inserted; and flux barriers provided around the magnets. The magnets include: first magnets 32; and second magnets 33 that are arranged in roughly a V-shape inwardly of the first magnets 32 in the radial direction. The flux barriers include: first flux barriers 34a that face the side surfaces 33a of the second magnets 33 at the outer sides thereof in the radial direction; and second flux barriers 34b that are arranged outwardly of the first flux barriers 34a in the radial direction. Each second flux barrier 34b comprises: a first side 34b1 which follows an outer peripheral surface tangent line TL of the rotor core 31; and a second side 34b2 which is located inwardly of the first side 34b1 in the radial direction and of which at least a part is formed along a side 34a1 of the first flux barrier 34a at the outer side thereof in the radial direction.

The invention provides a multilayer claw pole rotor and a motor. The multilayer claw pole rotor comprises at least two layers of claw pole rotor units. The claw pole rotor unit comprises a first rotor, a second rotor and a magnetic disk, the first rotor comprises a first rotor main body and a first claw, the second rotor comprises a second rotor main body and a second claw, and the first claw axially extends to the periphery of the second rotor main body towards the direction of the second rotor. The second claw also axially extends to the periphery of the first rotor main body towards the direction of the first rotor; in the projection plane of the axial end face of the first rotor, the circle center of each first claw does not coincide with the circle center of the first rotor, an eccentric distance e exists between the circle center of the peripheral face of each first claw and the circle center of the first rotor, the multiple first claws are provided with a first circumscribed circle, the radius between the circle center of the first rotor and the first circumscribed circle is R1, and the eccentric distance e meets the requirement that e is larger than 0.2 R1 and smaller than 0.7 R1. According to the invention, the problem of low utilization rate of a permanent magnet material of a permanent magnet motor in the prior art can be solved, and the problem of large torque pulsation is also solved.

This invention discloses a highly generalizable method for diagnosing open-circuit faults in multi-transistor converters of motor drive systems. This method addresses open-circuit faults in power devices caused by overcurrent surges, poor heat dissipation, and other factors, preventing damage to the motor and power grid equipment caused by output current distortion and increased torque ripple. The method analyzes the retention characteristics of the positive and negative regions of the three-phase stator current under steady-state operating conditions to construct a fault location function, and combines auxiliary variables to accurately distinguish between single-power and dual-power device open-circuit faults. This invention enables rapid location and accurate identification of complex open-circuit faults such as those in opposite phases on the same side or in opposite phases on opposite sides. It offers advantages such as high diagnostic accuracy, strong ability to distinguish mixed faults, and non-invasiveness, making it suitable for motor drive systems with high requirements for operational reliability and fault tolerance.

The utility model discloses a stator assembly, a motor and a vehicle. The stator assembly comprises an iron core part, a cover plate and a plurality of tooth boots. The iron core part comprises a plurality of iron cores and a plurality of coils, the iron cores are arranged at intervals in the circumferential direction of the stator assembly, and the coils are arranged on the iron cores respectively. The number of the cover plates is two, the two cover plates are arranged on the two opposite sides of the iron core part in the axial direction of the stator assembly respectively, a plurality of installation holes and a plurality of installation grooves are formed in the cover plates, and the installation holes correspond to the iron cores in a one-to-one mode and are used for fixing the iron cores. The plurality of tooth boots are respectively arranged in the plurality of mounting grooves, and the tooth boots correspond to the opening grooves between the two adjacent iron cores in the axial direction. According to the invention, the arrangement of the tooth boots can reduce the opening size of the open slot between the two adjacent iron cores, thereby reducing the leakage reactance of the slot and the tooth harmonic of the gap flux density, improving the torque pulsation of the motor, and improving the operation stability of the motor.

The application discloses a kind of humanoid robot linear joint permanent magnet motor design optimization method, this method includes: based on the mechanical characteristics of human gait cycle to establish knee joint connecting rod mechanism dynamics model, extract characteristic working condition point and establish screw-motor electromechanical matching criterion, using Latin hypercube sampling to obtain design sample point, establish permanent magnet motor multi-objective optimization model with limit torque, torque ripple, efficiency as target, then introduce evolutionary algorithm for global optimization, obtain Pareto non-inferior solution set;Finally, based on CRITIC-TOPSIS evaluation method, fusion objective data characteristics and subjective working condition demand, determine the optimal design scheme from Pareto non-inferior solution set.The design optimization method of the application can define the design requirements of permanent magnet motor, and can also scientifically distribute the target weight, ultimately can obtain the permanent magnet motor scheme highly matched with specific joint working condition, effectively improves the power performance and operating stability of humanoid robot linear joint.

The invention relates to a method for measuring torque using a torque sensor integrated in a robot arm joint (17), comprising the following method steps: in a calibration step, measuring torque using the integrated torque sensor and determining the position, speed and acceleration of a rotating element of the joint during idle rotation of the joint, thereby obtaining training data; -in a training step, performing a linear regression analysis to obtain a correction function indicative of the intrinsic dynamics of the robot arm joint, where the correction function is a linear combination of at least four basis functions: i. At least one friction torque basis function comprising a first speed dependent sigmoid function and / or a speed dependent linear function; and ii. At least one torque ripple basis function comprising a first position dependent periodic function; and iii. At least one inertial basis function comprising a first acceleration dependent linear function; and iv. At least one torque offset basis function, which is a constant; -in an operational measurement step, measuring the torque using the integrated torque sensor under load conditions and obtaining a corrected torque value on the basis of the measured torque value and a correction function.

The application discloses a high-precision model prediction current control system and control method of a double three-phase motor, and relates to the technical field of multiphase motor control. The application extends the traditional 12 virtual voltage vector control set, designs 24 virtual voltage vectors with equal amplitude and uniform phase angle under the premise of not losing voltage utilization rate, and improves control precision. A duty cycle calculation method based on minimum error is proposed, which can track the currents of d-axis and q-axis at the same time even in the case of a single effective virtual voltage vector, and guarantees optimal output duty cycle. In addition, the process of traversing all voltage vectors in the prediction control is simplified, and the calculation burden of the algorithm is reduced. The application improves the precision of model prediction control by extending the control set and reducing the calculation error of the duty cycle, reduces 5th and 7th harmonics, and improves torque ripple. Moreover, even under the action of 24 voltage vectors, the calculation amount is still low, and the execution efficiency of the algorithm is improved.

Provided in the present application are a rotor lamination and a forming method therefor, a rotor iron core, a servo motor and a robot. The rotor lamination comprises a lamination body (1), the lamination body (1) having a rotor outer circumference (2); under one pole, the rotor outer circumference (2) of the lamination body (1) is provided with a groove (3) recessed inwards relative to the rotor outer circumference (2) and / or a protrusion (4) protruding outwards relative to the rotor outer circumference (2). According to the rotor lamination of the present application, the stamping precision of the outer contour of the rotor lamination can be improved, allowing a reduction in the cogging torque and torque ripple of the electric motor, and thereby improving the positioning accuracy of the robot.

To secure reduction effect on noise caused by torque ripple, while reducing leakage of a magnetic flux.SOLUTION: A rotor 100 according to an embodiment includes a rotor shaft, a plurality of permanent magnets, and a rotor core 120. Formed in the rotor core 120 are a wide-angle flux barrier band 130 having wide-angle FBB openings 132, 133 or a narrow-angle flux barrier band 140 having narrow-angle FBB openings 142, 143, which has a plurality of electromagnetic steel plates and is formed in a substantially projecting shape with respect to a rotation center axis in the magnetic pole. Each of a circumferential angle Θ1a and a circumferential angle Θ1b formed by two wall surfaces of the wide-angle FBB openings and a d-axis is larger than each of a circumferential angle Θ2b and a circumferential angle Θ2b formed by two wall surfaces of the narrow-angle FBB openings and the d-axis, and Θ1b is larger than Θ1a.SELECTED DRAWING: Figure 8

This invention relates to a low-current harmonic direct torque control method for a dual three-phase permanent magnet synchronous motor (PMSM), belonging to the field of PMSM control technology. The method is as follows: S1: Establish mathematical models of the fundamental and harmonic subspaces of the dual three-phase PMSM under vector space decoupling, and clarify the voltage vector distribution characteristics of the two subspaces; S2: In the fundamental subspace, design a duty cycle modulation strategy based on the principle of minimizing the error vector, and an improved deadbeat flux linkage torque controller; S3: In the harmonic subspace, design an online learning harmonic canceller, using the least mean square algorithm to update the weight coefficients in real time; S4: Select the D1 vector set as the effective vector of the harmonic subspace and perform sector division; S5: Add the effective voltage vector action time of the fundamental and harmonic subspaces to generate the final switching sequence, which is output to the dual three-phase inverter to effectively suppress torque ripple and harmonic current of the dual three-phase PMSM.

The present application relates to a kind of large-diameter low magnetic resistance moment online balancing structure, including installation and removal mechanism, stator, rotor and shafting support mechanism, installation and removal mechanism is installed on stator, rotor is embedded stator and is connected with shafting support mechanism through rotor connecting seat after stator;Stator includes stator core assembly, stator housing and stator fixing frame, stator core assembly includes stator magnetic conducting ring and core positioning block, stator magnetic conducting ring with core positioning block is installed in stator housing, stator housing is clamped on stator fixing frame, stator housing and stator fixing frame are respectively provided with the stator housing processing gap and the stator fixing frame processing gap of adjusting stator magnetic conducting ring.Stator housing processing gap and stator fixing frame processing gap are adjusted to stator magnetic conducting ring by balancing structure, so that magnetic resistance moment reaches uniform condition in 360 ° circumference range.The present application balancing method realizes the effective control of magnetic resistance moment, inhibits the generation of torque ripple and noise, so as to improve the overall performance and survival rate of motor.

The invention provides a fault-tolerant control method and system for open-phase faults of a four-phase and three-phase permanent magnet synchronous motor, electronic equipment and a storage medium. Belongs to the technical field of motor control. The method is based on a 4DQ decoupling control framework, and an open-phase fault-tolerant control module is additionally arranged between a speed loop and a current loop. When the open-phase fault of the motor is detected, the module firstly identifies the number of sets of faulty windings, cuts off control signals of the faulty sets of windings, then averagely distributes q-axis total reference current output by a speed ring to the remaining healthy three-phase windings again according to the number of the faulty sets, and carries out necessary amplitude limiting processing. And finally, the current loop controller of each healthy winding drives the inverter to work according to the redistributed reference current. According to the invention, the structural advantage of independent isolation of the four-phase and three-phase motor windings is fully utilized, and the torque ripple is effectively suppressed and the stable operation of the motor is maintained through overload or derating operation of a healthy winding under the condition that a single set or multiple sets of windings have faults.

The utility model discloses a converter system, and relates to the technical field of vehicle engineering. The converter system comprises a converter body formed by cascading a plurality of same basic power subunits, the input end of the converter body is used for being directly connected with a single-phase traction network, and the output end of the converter body is used for independently driving a plurality of traction motors. The output end of the converter body is provided with a three-phase output filter capacitor. According to the converter system, the basic power subunits are cascaded to form the converter main body, so that the current-carrying capability and the voltage endurance capability can be improved; and the output end of the converter main body is provided with a three-phase output filter capacitor, so that when the transformer main body outputs voltage to drive the traction motor, the torque ripple and electromagnetic noise of the traction motor can be reduced.

To provide a stator which reduces torque ripple while suppressing reduction in torque of a motor, and a motor or a generator.SOLUTION: A stator 10 of concentrated winding comprises a plurality of main magnetic poles 11a around which coils are wound and auxiliary magnetic poles 13 provided between the plurality of main magnetic poles 11a. In the case of high load, the auxiliary magnetic poles 13 are magnetically saturated, thereby increasing interlinkage magnetic flux of the coils than in the case of low load.SELECTED DRAWING: Figure 2

The application discloses a low-pulsation inverse-cosine plus third-harmonic auxiliary salient pole type radial permanent magnet motor and a method for optimizing air gap harmonics, and belongs to the technical field of motor manufacturing. A novel radial permanent magnet synchronous motor with inverse-cosine plus third-harmonic auxiliary salient poles is provided, and the method can suppress air gap flux density harmonics and reduce torque ripple and average torque loss. The specific process is as follows: the rotor air gap flux density is proportional to the rotor magnetomotive force, and the main air gap flux density harmonic order affecting the torque ripple is determined. The inverse-cosine plus third-harmonic method is used to modify the auxiliary salient poles, so as to reduce the air gap flux density harmonics, especially the 9th, 11th, 19th and 21st harmonics causing the first and second order torque ripples, thereby reducing the torque ripple; since the third harmonic is not the main air gap flux density harmonic causing the torque ripple, the injection of the third harmonic can reduce the average torque loss.

The present invention relates to a drive control device for a synchronous motor. To provide a drive controller of a synchronous motor capable of suppressing torque ripples of sixth order, twelfth order, etc., which cannot be suppressed by a basic drive controller.SOLUTION: The drive control device of the synchronous motor comprises at least a means for generating a final current command value for suppressing a specified torque ripple and a current control means for performing discrete time control of a stator current so as to follow the final current command value, wherein a discrete time compensating current controller arranged in parallel to a PI current controller and having a pole on a unit circle with a zero point as an origin and multiplying a control gain and a control period by a control deviation is added to the discrete time current controller being a central device of the current control means.SELECTED DRAWING: Figure 5

This invention discloses a torque-stable two-phase brushless DC motor and its control method. The two-phase brushless DC motor includes a stator and a rotor. The stator includes a stator core and 4*n stator windings surrounding the stator core. The rotor includes a rotor core and 6*n permanent magnet poles surrounding the rotor core, where n is a positive integer, and adjacent permanent magnet poles have opposite polarities. This invention features high stator winding utilization efficiency, reduces the weight of the brushless DC motor, and exhibits low torque ripple, making it suitable for applications requiring continuous power output.