222 results about "Rotor flux" patented technology

The invention provides a parameter self-tuning control method for a permanent magnet synchronous motor, and relates to the technical field of synchronous motor control, and the method comprises the steps: firstly, monitoring a dynamic operation data set, including stator current, rotor flux linkage, rotating speed fluctuation quantity and load change characteristic parameters, of the permanent magnet synchronous motor in real time; secondly, feature relevance mapping is carried out based on multiple parameter combinations in the dynamic operation data set, initial parameter adjustment sets are generated, and each initial parameter adjustment combination comprises the mapping relation between the motor operation state and the target response index; dividing a plurality of parameter adjustment subsets according to the parameter correlation degree, configuring a dynamic error range, extracting a positive adjustment parameter from the first subset corresponding to the first operation state, and extracting a negative adjustment parameter from the second subset with the low correlation degree; and finally, training a dynamic parameter adjustment model by utilizing the positive adjustment parameters and the negative adjustment parameters, generating an optimized real-time parameter setting instruction set, realizing intelligent self-setting of the parameters of the permanent magnet synchronous motor, and improving the running performance of the motor.

The invention relates to an FOC control method based on an automobile air conditioner module motor without a Hall sensor, and belongs to the technical field of automobile electronics. The method comprises the following steps: injecting double-frequency voltage pulses into a stator in stages to position a rotor; collecting current through a sampling resistor and filtering to construct a rotor flux linkage distribution model, and presetting rectangular axis current in combination with noise reduction of a miniature acoustic sensor and air speed gear of an air conditioner; an extended Kalman filter observer is adopted to reversely deduce the load torque, and the torque change rate is monitored to trigger instantaneous load impact protection; the voltage space vector amplitude is corrected through voltage feed-forward compensation, a resistor-capacitor series filter circuit is additionally arranged, and phase dislocation pulse width modulation is adopted for resisting interference; and establishing a motor efficiency-rotating speed-load three-dimensional optimization method, starting dynamic flux-weakening control, and estimating the winding temperature through the stator resistance to adjust the flux-weakening depth. Accurate starting and dynamic load adaptation of the Hall-sensor-free motor are achieved, starting out-of-step and noise exceeding are avoided, and stable air volume of an automobile air conditioner and long-term reliable operation of the motor are guaranteed.

The invention discloses an AC excitation system rotor initial position on-line identification method and system, and the method comprises the steps: collecting a stator three-phase voltage signal when a stator is no-load, carrying out the Clarke conversion of the signal, obtaining a voltage component under a static coordinate system, and carrying out the low-pass filtering processing; calculating a stator flux linkage based on the stator current and the processed voltage component, and calculating a rotor flux linkage based on the rotor current; the rotor initial position offset is continuously accumulated through closed-loop adjustment by calculating the stator and rotor flux linkage angle and the phase difference until the phase difference approaches zero, and the accumulated rotor initial position offset is output; and combining the mechanical angle output by the encoder with the accumulated rotor initial position offset to obtain a corrected rotor position angle, and updating the corrected rotor position angle to an excitation system. According to the method, the in-phase characteristics of stator and rotor flux linkages are utilized, and the optimally designed low-pass filter is combined, so that the identification precision of the initial position of the rotor is remarkably improved, and the zero offset of the encoder is effectively compensated.

The invention discloses an iterative phase-locked limit cycle flux observer, a control method, a control device and a control system, and the control method comprises the following steps: collecting alpha-beta axis voltage and current signals of a motor, constructing an IPMSM mathematical model under an alpha-beta axis, and calculating to obtain a counter electromotive force vector of the motor; taking the motor back electromotive force vector as input, acquiring motor rotor flux linkage information through an iterative phase-locked limit loop flux linkage observer, and estimating a motor rotating speed and a position signal according to the motor rotor flux linkage information; and the rotating speed and the position signal of the motor are input into a motor closed-loop control system, so that position-sensorless closed-loop control of the permanent magnet synchronous motor is realized. According to the method provided by the invention, the problem of integral drift or phase lag of a traditional flux linkage observer can be avoided, the influence of direct current bias on flux linkage and position observation precision is effectively suppressed, the dynamic response capability of position sensorless control is remarkably improved, and a position estimation error generated in a dynamic process is suppressed.

The invention discloses an adaptive power control method for a duplex-winding induction generator system, and belongs to the technical field of generator control. The double-winding induction generator system is composed of a double-winding induction generator, an energy storage unit, a static excitation converter and a diesel engine. According to the self-adaptive power control method, control winding current is decoupled into excitation control and electromagnetic torque control through coordinate transformation based on rotor flux linkage orientation, independent adjustment of output power of the generator is achieved, passive regulation and control of power of an energy storage unit are achieved through control of electromagnetic torque of the generator, and the self-adaptive power control method is achieved. The problem that the control freedom degree of a single converter system is insufficient is solved. Besides, according to the control method adopted by the invention, a dynamic planning-based generator / energy storage unit power distribution strategy with minimum fuel loss as a target is adopted, so that the generator is ensured to always work in a high-efficiency interval of the diesel engine within a wide load change range, and the power generation cost is remarkably reduced.

The invention provides a touch feedback control method and device for a rotary knob, electronic equipment and a medium, and belongs to the technical field of switch control. The method comprises the following steps: converting a current Ia, a current Ib and a current Ic in a three-phase static coordinate system into a current Ialpha and a current Ibeta of a two-phase static coordinate system; the current I alpha and the current I beta of the two-phase static coordinate system are converted into current Id and current Iq under a two-phase rotating coordinate system with rotor flux linkage as orientation; the convergence speed of the driving motor in the dynamic response process is controlled and optimized by adopting a sliding mode variable structure; performing real-time setting through a zebra optimization algorithm to minimize overshoot and optimize convergence time; and the magnitude of the rotation feedback damping force is controlled by adjusting the current Iq. In this way, active rotating tactile feedback and pressing tactile feedback can be provided, and the intelligent interaction degree is improved.

The invention discloses a motor belt speed restarting control method, device and equipment and a medium, and the method comprises the steps: obtaining the counter electromotive force of a motor; determining a motor rotating speed reference value corresponding to the counter electromotive force; the motor is controlled to be started based on the motor rotating speed reference value and preset exciting current, and the preset exciting current is larger than rated exciting current of the motor. According to the technical scheme, the preset exciting current larger than the rated exciting current of the motor is set for the motor, the motor is controlled to be started according to the preset exciting current and the motor rotating speed reference value, the motor is started through the preset exciting current larger than the rated exciting current, and therefore the rotor flux linkage can be rapidly established by the motor, and the efficiency of the motor is improved. The motor can quickly reach the optimal operation state after restarting, and the effect of improving the belt speed restarting success rate of the motor can be achieved.

Disclosed in the present application are a double-rotor magnetic flux switching permanent magnet electric motor, a double-rotor magnetic flux switching permanent magnet electric motor optimization method and optimization device, a medium and a product. The double-rotor magnetic flux switching permanent magnet electric motor comprises an inner rotor, an outer rotor and an intermediate stator, wherein the intermediate stator comprises a stator core; permanent magnets are arranged inside the stator core on two sides thereof; the stator core comprises a plurality of toothed portions; and an excitation winding is arranged between every two adjacent toothed portions.

The invention relates to a sensorless brushless direct current motor direct torque control method based on robust extended Kalman filtering. The method comprises the following steps: acquiring stator voltage and current, and estimating an estimated rotor position, an estimated speed and an estimated electromagnetic torque of a motor through a robust extended Kalman filtering algorithm; determining a voltage space sector where a rotor flux linkage vector is located based on the estimated rotor position and the estimated speed of the motor; determining a target value based on the estimated electromagnetic torque and a reference electromagnetic torque, the target value being used to characterize a magnitude of desired electromagnetic torque adjustment; based on the voltage space sector where the rotor flux linkage vector is located and the target value, a voltage vector corresponding to the motor is obtained, and the voltage vector is used for driving the rotor flux linkage vector to rotate in the needed direction. By adopting the method, accurate control of the motor is realized without adopting a sensor.

The invention relates to the technical field of permanent magnet motors, in particular to a double-rotor hybrid excitation magnetic flux switching permanent magnet motor with double-C staggered teeth and magnetic flux leakage control, which comprises an outer rotor, a middle stator and an inner rotor, the middle stator is arranged between the outer rotor and the inner rotor, a plurality of first salient poles are uniformly distributed on the outer rotor, and a plurality of second salient poles are uniformly distributed on the inner rotor. A plurality of second salient poles are uniformly distributed on the inner rotor; the middle stator comprises m double-C staggered tooth type iron cores, m rectangular leakage magnetic iron cores, n tangentially magnetized I-type permanent magnets, an armature winding, a first set of excitation windings and a second set of excitation windings. The advantages of compact structure and high working efficiency of a double-rotor magnetic flux switching permanent magnet motor are reserved, an air-gap magnetic field is smooth and adjustable by adding the electro-magnetic winding, the problem of magnetic field coupling when the inner motor and the outer motor work simultaneously is effectively solved, the speed regulation range when the inner motor and the outer motor work independently is widened to a certain extent, and the service life of the motor is prolonged. Meanwhile, the leakage magnetic iron core is added, so that the problems of strong permanent magnetic potential and difficulty in flux weakening are solved.

The invention discloses a permanent magnet synchronous motor control method and system based on online parameter identification, and relates to the field of motor control, and the control method comprises the steps: building a motor mathematical model of a permanent magnet synchronous motor in a static coordinate system, and the mathematical model is used for describing the relation between stator voltage and current and rotor electrical angle and electrical angular velocity; constructing a flux linkage observer, estimating a rotor flux linkage by observing the stator voltage and current, and calculating the position and speed of the rotor based on the rotor flux linkage; a recursive least square method is adopted to carry out online parameter identification, and motor parameters are updated in real time to compensate the influence of parameter changes on the control precision. According to the position-sensorless control method provided by the invention, accurate rotor position and speed estimation can be realized, and efficient control is realized. In combination with a gain adjustment and compensation method, the system can automatically adjust a control strategy according to different working conditions during motor operation, and the stability, precision and robustness of the system are improved.

The invention is suitable for the technical field of energy storage, and provides a flywheel energy storage charging control method, which comprises the following steps of: 1, modeling a high-speed permanent magnet synchronous motor, establishing a flywheel energy storage system type, simplifying a PMSM mathematical model, constructing a PMSM model under an ABC coordinate system, and converting to a PMSM model under a d-q coordinate system; and 2, performing model prediction current control on the MRAS, performing double-vector model prediction current control, performing model reference adaptive method, performing parameter identification precision verification based on the MRAS, and adopting a parameter step-by-step identification method based on the MRAS to solve the problem that the model prediction current control height depends on prediction model accuracy, so that the accuracy of the model prediction current control is not influenced. The problem that prediction current control performance of a double-vector model is reduced due to mismatching of model parameters is solved, the identification precision of rotor flux linkage, stator resistance and stator inductance is high, meanwhile, the speed regulation range is widened, the dynamic response characteristic is improved, and the motor model can reflect the actual situation more accurately.

The present invention relates to the technical field of motor control, and disclosed are a motor control method and apparatus, a medium, and an electronic device. The method comprises: acquiring feature parameters of a motor; on the basis of the feature parameters, determining a stator flux parameter of the motor; on the basis of the stator flux parameter, performing compensation processing to obtain a target rotor flux parameter; on the basis of the target rotor flux parameter, determining a locking and synchronization angle of the motor; on the basis of the feature parameters, acquiring the current control angle of the motor; and on the basis of the current control angle and the locking and synchronization angle, determining a control angle of the motor.

A method for controlling an electrical converter for driving an electrical machine comprises the steps of: estimating a stator flux vector depending on at least one measurement in the electrical converter; receiving a rotor speed of the electrical machine; determining an optimized pulse pattern for the electrical converter depending on the rotor speed; determining a rotor angle of a rotor flux vector depending on the rotor speed; determining a reference stator angle of the stator flux vector depending on the rotor angle; determining a reference stator flux vector depending on the optimized pulse pattern and the reference stator angle; determining a difference between the reference stator flux vector and the estimated stator flux vector; modifying switching instants of the optimized pulse pattern, such that the difference is minimized; and applying at least a part of the modified optimized pulse pattern to the electrical converter.

The invention relates to a permanent magnet synchronous motor control method, a controller, a compressor and a household appliance, and the method comprises the steps: firstly obtaining the stator current of a motor, determining a stator flux linkage theoretical value of the motor according to the stator current, and then defining a stator flux linkage estimation value function of the motor, determining a rotor flux linkage characteristic value according to a stator flux linkage estimation value function of the motor, obtaining a first deviation function and a second deviation function, solving a stator flux linkage estimation value when the second deviation function is a minimum value, and determining the stator flux linkage estimation value meeting a constraint condition as a target stator flux linkage value; and finally determining the rotating speed of the motor according to the target stator flux linkage value, and controlling the motor according to the rotating speed of the motor. According to the method, the target stator flux linkage value after interference removal is accurately estimated by taking the characteristics that the rotor flux linkage is a constant value and is not related to the rotor rotating speed as well as the condition that the first deviation function is zero as a constraint condition, so that the accuracy of motor rotating speed estimation is improved, and the motor is accurately controlled.

The invention provides an MRAS permanent magnet synchronous motor parameter online identification method based on BP neural network optimization, and the method comprises the steps: constructing two BP neural network models, carrying out the offline training optimization of the two models, and obtaining an optimal neural network model which can accurately predict the flux linkage of a rotor and the inductance of a stator; based on an MRAS step-by-step identification strategy, two-stage motor parameter step-by-step identification units are built, the two optimal neural network models are embedded into the corresponding motor parameter step-by-step identification units, and based on the problem that the stator resistance identification effect of the BP neural network is poor, the two optimal neural network models are embedded into the corresponding motor parameter step-by-step identification units; according to the invention, the BP neural network and the adaptive rate unit are established in the second MRAS parameter identification unit, and the online dynamic identification of the stator resistance and the stator inductance is realized through the combination of the BP neural network and the adaptive rate unit. According to the method, an off-line training-on-line identification mode is adopted, the complex parameter setting process in a traditional method is avoided, the identification efficiency is remarkably improved, and the identification result is accurate.

The present invention relates to a speed sensorless induction motor wide-speed-range stable operation system and a method. According to the system, orthogonal characteristics of a rotor flux linkage are used to correct a voltage model of an induction motor, a rotor flux linkage observer and a stator current extended state observer are established, and a motor observation model is reconstructed; an extended state variable is taken as a feedback item to ensure the stability of rotor flux linkage estimation; and speed information is extracted from the rotor flux linkage estimation by means of phase-locked loop, thereby implementing induction motor sensorless control. The present invention involves a reasonable design, can effectively improve the operation stability of a speed sensorless induction motor in a low-speed power generation mode and a high-speed range, and achieves wide-speed-range sensorless stable control.

The invention discloses an intelligent self-adaptive control method for a diesel generating set, which aims at the problems of slow load fluctuation response, poor system stability and the like of the traditional diesel generating set, and comprises the following steps: triggering a quick response mechanism by monitoring a load power change rate in real time, and dividing a load into low, medium and high load areas by adopting a piecewise linearization power distribution strategy; matching an optimal power combination in a power distribution table generated offline by combining an energy storage SOC state; the winding current is decoupled and controlled through rotor flux linkage directional coordinate transformation, the electromagnetic torque is rapidly adjusted through a PI controller, and cooperative power output is achieved in cooperation with space vector pulse width modulation. The preset rule limits that the energy storage power does not exceed 80% rated value and the SOC is maintained at 20%-80%, and the power distribution table is stored in the digital signal processor for real-time execution. According to the method, the response time can be shortened, the controller load is reduced, and the system stability and the fuel economy under complex working conditions are improved.

The invention provides a multi-input and multi-output frequency coupling admittance modeling method for a follow-up network fan, and belongs to the technical field of large-scale follow-up network type and follow-up network type fan frequency coupling admittance modeling. The technical problem that a network following type GFL and network constructing type GFM doubly-fed fan series-parallel system in a wind power plant lacks an accurate small-signal modeling and analysis method is solved. According to the technical scheme, the method comprises the following steps: S1, establishing an open-loop doubly-fed motor self admittance considering stator and rotor flux linkage dynamics; s2, obtaining frequency domain multiple-input multiple-output admittances of the following network type doubly-fed fan and the constructed network type doubly-fed fan; s3, obtaining a unified multiple-input multiple-output admittance frequency domain model containing a closed loop interconnection system formed by the following network type doubly-fed fan admittance YGFL and the construction network type doubly-fed fan admittance YGFM; and S4, quantitatively evaluating a phase-locked loop parameter and a virtual synchronous control parameter. According to the invention, accurate determination of frequency coupling oscillation is realized.

The invention provides an outer rotor 3D magnetic flux permanent magnet synchronous motor, which comprises a rotor assembly, a stator assembly and a rotating shaft, the rotor assembly comprises a radial permanent magnet group and an axial permanent magnet group, the stator assembly comprises a stator iron core and an armature winding, the axial end parts of the two sides of the stator iron core are connected with magnetic conductive yokes, the end surfaces of the magnetic conductive yokes are provided with magnetic conductive shoes, and the magnetic conductive shoes are connected with the armature winding. A radial winding groove is formed between every two adjacent magnetic conductive boots; the armature winding comprises a plurality of winding units, and the bent parts at the two ends of each winding unit are embedded in the radial winding grooves in the two sides of the magnetic conductive shoe. According to the motor provided by the embodiment of the invention, the magnetic conductive shoes are creatively used at the end part of the stator core to guide the windings to carry out back winding arrangement, an axial armature magnetic field is generated, a radial magnetic circuit and two-side end part axial magnetic circuits are combined to form a hybrid excitation 3D magnetic flux structure, and radial magnetic flux and two-side axial magnetic flux cooperatively do work outwards in a parallel connection manner, so that the motor is more compact in structure. And the torque density and the loading capacity of the motor are obviously improved.

The application provides a method for observing rotor flux of an alternating current motor, and belongs to the technical field of motor control. The method comprises the following steps: calculating rotor observation flux based on a first voltage-type flux calculation model and stator voltage and stator current in a two-phase static coordinate system; obtaining an amplitude deviation by subtracting the amplitude of the rotor rated flux from the amplitude of the rotor observation flux, and obtaining a deviation compensation quantity by multiplying the amplitude deviation by a proportional integral operation; and compensating and correcting the first voltage-type flux calculation model based on the deviation compensation quantity to obtain a voltage-type flux calculation model with compensation correction, so that the amplitude of the rotor observation flux converges. The application converges the rotor observation flux to the rotor given flux by connecting a correction link based on the traditional voltage-type flux calculation model, and finally realizes accurate flux position observation.

The utility model relates to the technical field of squirrel-cage synchronous motors, in particular to a rotor punching sheet and a stator punching sheet on a squirrel-cage synchronous motor of a refrigerator compressor, which comprise 24 stator grooves including two special-shaped grooves A and two special-shaped grooves B, two punching sheet yoke parts 1 form a tip structure of the stator punching sheet, and the included angle of the tip end of the rotor groove is set to be 150-165 degrees. According to the technical scheme of the utility model, one side of the stator punching sheet structure adopts the traditional long-edge design, the other side adopts the pointed-end structure, and four of the 24 slots adopt the special-shaped slot design, so that the size rationality of the yoke part of the motor is ensured, the rationality of the magnetic circuit of the motor in design is ensured, the utilization rate of silicon steel of the motor is improved, and the consumption of silicon steel is reduced; the groove-shaped tooth tip parts of the rotor punching sheet are distributed at 150-165 degrees, and on the premise that the tooth width and the groove-shaped length of the rotor are not changed, the cast aluminum volume of the rotor is improved, so that the impedance of the rotor is improved, the magnetic flux density of the rotor is increased, the maximum torque of the motor is improved, and the starting performance of the compressor is improved.

The invention relates to an adaptive system and method for controlling brushless direct current (BLDC) motors (20). The invention estimates the motor's stator resistance and rotor magnetic flux online based on the error in the motor currents. These estimated values ​​are applied to an input-output feedback linearization (IOFL) control law that compensates for the motor's nonlinear dynamics. Speed ​​control is provided by a single PI controller (31) whose gain parameters are determined by Particle Swarm Optimization (PSO). This configuration reduces torque ripple, increases efficiency, and offers superior control performance, especially in precision applications such as unmanned aerial vehicles.

To provide a mathematical model that can be used for simulation, characterization-analysis, and control for a three-phase synchronous motor that generates iron loss in a stator, as well as a simulating device, characterization analysis device, or control device for a synchronous motor.SOLUTION: A mathematical model solves a problem regarding a stator reaction flux and rotor flux constituting a stator flux by providing an equivalent iron loss resistance so that iron losses occur in the stator reaction flux, while the iron losses does not occur in the rotor flux, and a voltage drop due to the equivalent iron loss resistance and a back electromotive force due to the stator reaction flux are roughly equal.SELECTED DRAWING: Figure 2

A three-phase squirrel cage asynchronous motor control method based on an anti-disturbance observer first constructs a dynamic mathematical model and state space equation of the asynchronous motor in a synchronous rotating orthogonal coordinate system oriented by the rotor flux; based on the state equation of the asynchronous motor, a speed loop disturbance observer, a flux loop disturbance observer, a d-axis current loop disturbance observer, and a q-axis current loop anti-disturbance observer are designed; then a nonlinear controller of the asynchronous motor is designed based on the backstepping control theory; finally, the disturbance observer and the controller are combined to design a speed control strategy based on flux estimation to achieve speed control of the three-phase squirrel cage asynchronous motor. The present invention improves the torque response of the system by integrating the disturbance observer and the nonlinear controller, enhances the operating level of the system under load changes and motor parameter perturbations, improves the robustness of the system, and at the same time improves the complexity of the traditional parameter adjustment method and improves the practicality.

In this method for controlling a generator motor, a motor torque command value is generated on the basis of a motor rotational speed command value and a motor rotational speed estimated value of the generator motor such that the generator motor rotated by an engine rotates following the motor rotational speed command value. In a method for controlling a generator motor in which a voltage command value for driving the generator motor is generated on the basis of a motor torque command value and a current detection value of the generator motor, the current detection value is input to a state observer that represents a voltage equation by a [gamma] [delta] axis having a prescribed phase difference with respect to a dq axis. A phase error estimation value and a motor rotation speed estimation value are calculated by inputting a voltage command value as a terminal voltage and calculating a rotor magnetic flux estimation value of the generator motor, the voltage equation representing the relationship between the current detection value and the terminal voltage of the generator motor through the dq axis of the generator motor, and the voltage command value representing the relationship between the current detection value and the terminal voltage of the generator motor through the dq axis of the generator motor. The parameter or the phase error estimation value constituting the state observer is corrected so that the deviation between the motor torque command value and the engine torque command value becomes small.

The invention discloses an induction motor control method and system and a medium. The control method comprises the following steps: acquiring a d-axis current # imgabs0 #, a q-axis current # imgabs1 #, a q-axis voltage # imgabs2 #, a d-axis voltage # imgabs3 # and a slope given frequency # imgabs4 # of a stator side of an induction motor at the current moment in real time; and the observer estimates the synchronous frequency # imgabs10 #, the rotor rotating speed # imgabs11 #, the slip frequency # imgabs12 #, the rotor magnetic field angle # imgabs13 # and the rotor flux linkage vector # imgabs14 # of the induction motor in real time according to the d-axis current # imgabs5 #, the q-axis current # imgabs6 #, the q-axis voltage # imgabs7 #, the d-axis voltage # imgabs8 # and the slope given frequency # imgabs9 # at the current moment. Whether the slope given frequency # imgabs15 # is smaller than a set threshold value # imgabs16 # or not is judged, and switching between the first control stage and the second control stage is conducted according to the judgment result. Current and rotating speed double-closed-loop control is adopted in the first control stage, speed fluctuation of the first control stage can be effectively restrained, on-load output current is reduced, current impact at the switching moment of the first control stage and the second control stage is reduced, and the switching stability between the first control stage and the second control stage is improved.

A method (100) for calibrating the offset angle (PhiO) of a field orientation regulator of a motor (210) between the angle signal (W) of a position sensor (220) and the direction of the rotor flux (RF), comprising the steps of: periodically changing (120) a current vector (Is) along a constant torque line; determining (130) a rotational speed signal (n_t) of the position sensor (220) of the motor (210); and calibrating (140) the offset angle (PhiO) based on the determined rotational speed signal (n_t).

The application provides a motor operation control method and device and a computer device, which comprises obtaining an operation temperature and a quadrature axis current operation parameter of a motor; determining a direct axis current correction parameter of the motor based on the operation temperature and the quadrature axis current operation parameter; and determining a direct axis current operation parameter of the motor according to a calibration current two-dimensional table of the motor and the direct axis current correction parameter. The direct axis current correction parameter is obtained based on a rotor flux linkage change parameter of the motor. By adjusting the direct axis current operation parameter based on the operation temperature according to the characteristic relationship between the flux linkage and the temperature during the operation of the motor, the voltage saturation phenomenon caused by the temperature change is reduced, the voltage saturation is avoided in advance, and the operation reliability of the motor is improved.

The present invention belongs to the field of AC servo systems and discloses a method and system for online identification of the rotor time constant of a sensorless induction motor based on a complex coefficient flux observer. The method comprises: estimating the rotor flux using a complex coefficient rotor flux estimator; injecting a biased sinusoidal excitation into the d-axis to obtain the rotor flux and filtered stator current along the dq axes through park transformation; online identification of the rotor time constant using a designed rotor time constant estimator based on a sliding mode observer; and estimating the stator frequency and rotor position using a phase-locked loop. The present invention decouples rotor time constant identification from rotor speed estimation, enabling parallel estimation of the two. The designed rotor flux estimator effectively suppresses DC bias and higher harmonics in back electromotive force. Compared to the traditional least squares method, the designed rotor time constant estimator based on a sliding mode observer improves the robustness of the estimation algorithm while ensuring convergence speed.