1025 results about "Counter-electromotive force" patented technology

The invention discloses a hybrid effective flux linkage observer and a permanent magnet synchronous motor control method, device and system. The method comprises the following steps: carrying out Clarke conversion on an obtained three-phase current of the permanent magnet synchronous motor to obtain a current in a static coordinate system, and carrying out park conversion based on rotor position information to obtain a current in a synchronous rotating coordinate system; the effective flux linkage of the permanent magnet synchronous motor is obtained through the hybrid effective flux linkage observer; on the basis of the obtained effective flux linkage of the permanent magnet synchronous motor, dead-zone compensation voltage is obtained through self-adaptive gain dead-zone compensation calculation based on back electromotive force reconstruction, and the rotating speed and the rotor position of the permanent magnet synchronous motor are obtained through phase-locked loop calculation; according to the rotating speed and the rotor position of the permanent magnet synchronous motor, the current under the synchronous rotating coordinate system, the dead zone compensation voltage and the obtained reference rotating speed and reference current, the reference voltage of the motor at the k moment is obtained through a rotating speed loop and a current loop and used for achieving low-speed position-sensorless control over the permanent magnet synchronous motor.

The invention relates to the field of intelligent control of electromagnetic appliances, and provides a control method and system for online fault diagnosis of a magnetic latching relay, and the method comprises the steps: responding to an external control instruction, collecting real-time bus voltage and real-time environment temperature data, constructing environment state characteristics through a magnetothermal coupling algorithm, and generating an initial PWM drive duty ratio; pulse modulation voltage is loaded, a current sampling sequence is collected, a current change rate sequence is obtained through moving average filtering and electromechanical coupling decoupling, extreme value searching is executed to extract counter electromotive force distortion characteristics, and a dynamic current sequential sequence is generated; a fusion input tensor is constructed, armature state probability distribution is output through a gating circulation unit, and a real-time energy compensation instruction is generated in a displacement interval before closing; and according to the real-time energy compensation instruction, respectively generating an enhanced driving waveform, a delayed driving waveform or a vibration driving waveform. According to the method, multi-mode physical characteristic perception and depth time sequence deduction are fused, and online fault diagnosis and active intervention closed loop of the magnetic latching relay are realized.

The invention discloses an axial winding complementary type hybrid excitation high-speed magnetic flux reverse motor, and belongs to the technical field of power generation, power transformation or power distribution. The motor comprises a six-slot stator iron core, a four-tooth rotor iron core, a set of annular winding serving as an excitation winding and a set of concentrated winding serving as an armature winding, permanent magnet groups are attached to the inner surface of the tooth part of the stator core, two groups of axial permanent magnets are opposite in polarity, and two groups of circumferential permanent magnets are opposite in polarity; and the rotor iron core is formed by laminating a plurality of rotor iron core sections which have a mechanical angle of 45 degrees in the axial direction. The motor has the magnetic field adjusting capacity and has the advantages of being small in flux linkage, counter electromotive force sine, cogging torque and torque fluctuation, extra rising voltage caused by strong armature reaction during high-speed operation can be reduced through flux weakening, torque during low-speed operation can be improved through flux increasing, and due to the fact that the number of poles is small, loss is small during high-speed and high-frequency operation, and the motor is high in reliability. Compared with other magnetic flux reverse motors, the magnetic flux reverse motor is more suitable for high-speed operation.

The invention relates to the technical field of power systems, in particular to a parameter prediction and control method and system of a sensorless motor. The method comprises the following steps: acquiring a sampling stator current and a sampling stator voltage of a motor and a motor rotating speed observation value obtained through an orthogonal phase-locked loop, and performing coordinate transformation on the sampling stator current to obtain a two-phase static coordinate system current; inputting the sampled stator voltage, the two-phase static coordinate system current and the motor rotating speed observation value into a sliding mode observer to obtain a back electromotive force observation value; inputting the back electromotive force observation value into a pre-constructed cross feedback frequency adaptive filter, eliminating harmonic waves and extracting a fundamental component to obtain a filtered fundamental wave back electromotive force observation value; and normalizing the fundamental wave back electromotive force observation value, and inputting the normalized fundamental wave back electromotive force observation value into an orthogonal phase-locked loop to obtain a motor rotor position prediction value and a rotating speed prediction value. By adopting the cross feedback frequency adaptive filter, the quality of the back electromotive force signal is improved, and the accuracy of rotor position and speed estimation is also remarkably 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 discloses a motor control method and device, a motor, an air compressor, a storage medium and a computer program product, and the method comprises the steps: carrying out the processing of the components of the stator voltage of the motor on the alpha and beta axes and the components of the stator current of the motor on the alpha and beta axes through a preset sliding mode observer module, and carrying out the control of the motor; the components of the counter electromotive force estimated value of the motor on the alpha and beta axes are obtained; based on the components of the back electromotive force estimation value of the motor on the alpha axis and the beta axis, after a preset phase-locked loop module and a preset staged angle compensation module are used for processing, a rotor electrical angular speed estimation value of the motor and a rotor electrical angular position estimation value of the motor are obtained, and control over the motor is achieved. According to the scheme, by combining the sliding mode observer module, the phase-locked loop module and the staged angle compensation module, the rotor electrical angular velocity estimation value and the rotor electrical angular position estimation value of the motor are determined, sensorless control over the motor is achieved, and the control performance of the motor is improved.

The invention discloses a permanent magnet synchronous motor non-inductive control method, and belongs to the field of permanent magnet synchronous motor control. Comprising the following steps: firstly, selecting stator current in the permanent magnet synchronous motor, defining a system state equation and a mechanical motion equation of the permanent magnet synchronous motor, then designing an exponential sliding mode speed controller, and finally designing a hyperbolic tangent function-based super-spiral sliding mode observer to observe counter electromotive force. And obtaining the rotating speed of the motor by using an arc tangent function. According to the hyperbolic tangent function-based super-spiral sliding mode observer, smooth transition can be provided near a sliding mode surface, high-frequency switching caused by small interference is avoided, system buffeting is obviously reduced, the designed speed controller can quickly respond under the condition that the rotating speed is quickly changed or load disturbance is relatively large, and the system stability is improved. And meanwhile, the problem of integral saturation in a PI speed controller is avoided, the robustness of the system is improved, and the buffeting effect is inhibited.

The invention relates to the technical field of motor control, and particularly provides a permanent magnet synchronous motor sensorless control method, which comprises the following steps of: designing a front-stage non-smooth extended state observer according to a voltage equation of a permanent magnet synchronous motor, and estimating the back electromotive force of the motor by using the front-stage non-smooth extended state observer; calculating the position error of the motor rotor by using the back electromotive force estimated value; and designing a post-stage non-smooth extended state observer according to the dynamic model of the permanent magnet synchronous motor, taking the position error as an input quantity, and extracting and outputting motor rotor position estimation and electric angular velocity estimation through the post-stage non-smooth extended state observer. According to the invention, the two cascaded non-smooth expansion state observers replace a traditional sliding mode observer and an orthogonal phase-locked loop structure, so that the extraction precision of position and speed information is effectively improved, and the dynamic performance and the steady-state performance of the permanent magnet synchronous motor sensorless sensor are improved.

Various boost circuits that are used to improve or reduce the time needed to transition an electric machine from an off-state to an on-state at the start of a next pulse during pulsed controlled operation. With these various boost circuits, the naturally generated Back Electromotive Force or “BEMF” that is induced when an electrical machine transitions from the on state to the off state at the end of an on pulse is harvested, rectified, and stored on a storage device. The harvested energy is then made available to the electric machine as a “boost” voltage at the onset of the next on pulse, resulting in a reduced transition time from the off-state to the on-state.

The invention relates to the technical field of motor control, in particular to a permanent magnet synchronous motor sensorless control method based on an extended state observer. The sensorless control method for the permanent magnet synchronous motor is characterized by comprising the following steps: establishing a mathematical model of the permanent magnet synchronous motor under a static coordinate system; designing an improved extended state observer based on the mathematical model, and realizing the estimation of the back electromotive force with low phase lag; and processing the obtained low-phase-lag back electromotive force through a phase-locked loop, and extracting position information and rotating speed information of a rotor of the permanent magnet synchronous motor. Phase lag and amplitude attenuation during back electromotive force observation can be effectively compensated, and the estimation precision of the rotor position is improved.

The invention provides a braking method and device of a linear motor, electronic equipment and a storage medium. The method comprises the steps that if the driving voltage of the linear motor after the current moment is smaller than the preset driving voltage, the braking voltage of the linear motor in the second integer number of half cycles is calculated based on the driving voltage before the current moment and the back electromotive force of the linear motor in the first integer number of half cycles after the current moment, the time length of the second integer number of half cycles is the same as that of the first integer number of half cycles; and whether the maximum value of the back electromotive force of the linear motor in the third integer half cycle is larger than or equal to the preset back electromotive force is judged, and whether the linear motor is braked or not is determined based on the judgment result. In this way, efficient and accurate braking of the linear motor can be achieved.

The invention discloses a BLDC (brushless direct current) driving parameter self-tuning embedded system and method for multiple equipment types, and the method comprises the steps: constructing a BLDC unified mathematical model containing an electromagnetic torque equation, a back electromotive force equation and a mechanical motion equation, and building a nonlinear mapping relation library of motor type identification codes and a key electrical parameter set; a predefined multi-mode excitation signal sequence is injected into the to-be-driven BLDC motor, dynamic response data are synchronously collected, and the dynamic response data are used for representing the characteristics of the key electrical parameter set; based on collected dynamic response data, equivalent inductance and equivalent resistance in a key electrical parameter set are decoupled and extracted through a frequency domain impedance analysis method, and meanwhile, a counter electromotive force coefficient and rotational inertia in the key electrical parameter set are identified by combining time domain counter electromotive force zero crossing point detection with rotating speed differential operation. Based on a motor fingerprint feature library and a fuzzy adaptive architecture, multi-model debugging-free plug-and-play is realized, and stable control performance is maintained under a dynamic working condition.

The invention discloses a phase voltage reconstruction method and device of a permanent magnet synchronous motor, a computer program product and a rotor position observation method and device.The phase voltage reconstruction method comprises the steps that three-phase PWM duty ratio signals and direct-current bus voltage of an inverter are collected, and ideal phase voltage is calculated through the duty ratio signals and the direct-current bus voltage; and dynamically correcting the error of the ideal phase voltage based on nonlinear characteristic compensation of IGBT / SiC. And on the basis of voltage reconstruction, a back electromotive force adaptive controller and a permanent magnet synchronous motor rotor position observer of an orthogonal phase-locked loop, full-speed-domain high-precision position estimation is realized by fusing a phase voltage reconstruction algorithm and expanding dynamic tracking capability of an EMF model and a QPLL, performance defects of a traditional method under low-speed and dynamic working conditions are overcome, and high-precision position estimation is realized. And the CPU resource consumption is high.

The invention provides a control method and system of a permanent magnet synchronous motor, computer equipment and a medium, and belongs to the field of motor control, and the method comprises the steps: obtaining stator current and voltage signals of the permanent magnet synchronous motor; constructing and operating a second-order sliding mode observer to output a stator current observation value; based on the current observation error and the change rate thereof, constructing a mixed sliding mode surface containing a linear term and a nonsingular terminal term, and designing a sliding mode control law; the control law is fed back to an observer to correct the observation process, and meanwhile two-phase observation counter electromotive force which is free of buffeting and does not need low-pass filtering is directly exported; closed-loop demodulation is carried out on the back electromotive force through a phase-locked loop, estimated values of the rotor position and the rotating speed are extracted, and finally position-sensorless vector control of the permanent magnet synchronous motor is achieved. According to the method, the buffeting phenomenon of a traditional sliding-mode observer is inhibited, a low-pass filter is avoided, phase lag is eliminated, and the estimation precision and the dynamic response performance of the system are improved.

The invention discloses a high-speed brushless direct current motor torque ripple suppression method, device and equipment and a storage medium, and belongs to the technical field of motor control. The method comprises three steps of adaptive harmonic suppression processing, phase compensation angle calculation and dynamic phase compensation. According to the invention, the center frequency is dynamically adjusted through the adaptive harmonic wave notch filter, the dominant harmonic component is inhibited in real time, and in combination with cascade delay signal elimination, 6k fixed subharmonics are filtered through the CDSC filter, so that a fundamental wave current signal is obtained; park transformation is carried out on the fundamental wave current based on an FOC algorithm, a PI controller is utilized to generate a phase delay angle according to a d-axis current error, and then a reference current compensation module dynamically compensates a current reference value to ensure phase synchronization of phase current and back electromotive force. Compared with the prior art, additional hardware equipment is not needed, and the torque ripple of the BLDC is reduced.

The invention relates to the technical field of vehicle control, and discloses a pure electric commercial vehicle resolver observation mechanism which comprises the following steps: in a whole vehicle driving state, judging whether to enter an observation mode or not, if the rotating speed of a motor is greater than an observation threshold value, entering the observation mode; if the rotating speed of the motor is smaller than the observation threshold, the observation mode is not entered or quitted; after entering the observation mode, calculating according to an LO observation model to obtain a back electromotive force observed quantity; inputting the back electromotive force observed quantity into the phase-locked loop model, and calculating to obtain a target observed quantity; meanwhile, a real signal is acquired and decoded by the rotary transformer; the target observed quantity and the real signal both comprise an angle and an angular velocity; and comparing the real signal with the target observed quantity to judge whether fault early warning is needed or not and judge whether the real signal meets the observation expectation or not. The real state of the driving system can be accurately observed, the robustness and reliability are high, and the operation efficiency is high.

The present invention discloses a method, device, equipment, and medium for suppressing motor back-electromotive force harmonics. The method includes: obtaining the three-way back-electromotive force of a synchronous motor; transforming the three-way back-electromotive force to obtain a direct-axis back-electromotive force and a quadrature-axis back-electromotive force; performing a Fourier transform on the quadrature-axis back-electromotive force and extracting the amplitude, frequency, and initial phase of each order harmonic of the quadrature-axis back-electromotive force; reconstructing each order harmonic of the quadrature-axis current based on the amplitude, frequency, and initial phase of each order harmonic of the quadrature-axis back-electromotive force; superimposing each order harmonic of the quadrature-axis current to obtain a reconstructed quadrature-axis current; and injecting the reconstructed quadrature-axis current into the quadrature-axis back-electromotive force to obtain the original torque representation value. This solution achieves suppression of motor back-electromotive force harmonics, with excellent harmonic suppression effect.

The invention discloses a permanent magnet synchronous motor temperature monitoring and demagnetization early warning method based on chaotic signal injection and multi-parameter fusion. Comprising the steps of 1, generating a wide-spectrum chaotic signal based on a Lorenz chaotic system, and injecting the wide-spectrum chaotic signal into a d-axis voltage channel of a d-q-axis mathematical model of the permanent magnet synchronous motor; 2, identifying stator resistance RS and d-axis inductance Ld by using a least square method; 3, a Kalman state space model with the winding temperature Tw and the magnetic steel temperature Tm as state variables is constructed, the resistance Rs and the inductance Ld which are measured in real time are fused, the observation noise covariance R is adjusted in a self-adaptive mode, and the winding temperature Tw and the magnetic steel temperature Tm are output in a decoupling mode; step 4, establishing a motor back electromotive force model to calculate a real-time flux linkage psi f, and calculating a motor temperature rise rate # imgabs0 # through a sliding window weighted average method; and step 5, performing demagnetization risk grading early warning according to the flux linkage and the temperature rise rate of the motor.

A controller for a permanent magnet synchronous motor includes a first control loop having a first filter. The first filter has a back-EMF voltage vector input, a magnetic flux vector output with a constant phase shift that is independent of motor speed, and an amplitude response that is inversely proportional to rotor electrical frequency. The first control loop is configured to: generate an adjusted magnetic flux vector from the magnetic flux vector output by the first filter and compensate for the constant phase shift introduced by the first filter; estimate the rotor electrical frequency from the adjusted magnetic flux vector; and feedback a filtered version of the rotor electrical frequency estimate to the first filter as an estimation of the rotor electrical frequency.

The invention discloses a rotor punching sheet, a motor, a compressor and refrigeration equipment, the rotor punching sheet comprises a punching sheet body, the end face of the punching sheet body is provided with a plurality of structure groups, each structure group comprises a first magnetic isolation groove, a magnetic isolation bridge and a mounting groove, the mounting groove is internally provided with a permanent magnet, and the length of the permanent magnet is w1; a mounting groove is formed in the punching sheet body, a first magnetic isolation groove is formed between each of two ends of the mounting groove and the outer peripheral surface of the punching sheet body, so that a magnetic isolation bridge is formed between each first magnetic isolation groove and the outer peripheral surface of the punching sheet body, the length of the magnetic isolation bridge is w2, and the relation range of w1 and w2 is that w2 / w1 is greater than or equal to 0.3 and less than or equal to 0.6. According to the technical scheme, on the premise that the mechanical structure strength of the rotor is guaranteed, the optimal pole-arc coefficient of the motor can be achieved, the no-load back electromotive force harmonic distortion rate, the cogging torque and the torque pulsation of the motor are reduced, the noise vibration of the motor is reduced, and the magnetic leakage is reduced, so that the performance of the motor is improved.

The invention discloses a humanoid robot joint motor control method with model prediction control, and relates to the technical field of robot motion control. The method is used for solving the problems of control instruction infeasibility and model disturbance caused by voltage saturation during high-speed motion. An error state space model of a joint motor system is established, and non-linear terms such as gravity are used as nominal feed-forward quantities for stripping; then, the rotating speed of the motor and the bus voltage of the driver are collected in real time, the back electromotive force is calculated, and the voltage margin is mapped into a dynamic torque physical limit value at the current moment; and meanwhile, estimating an unmodeled lumped disturbance value of the model by using an extended state observer. And finally, taking the dynamic limit as a real-time inequality constraint, introducing a disturbance value correction prediction equation, constructing and solving a quadratic programming problem, extracting an optimal compensation torque, superposing the optimal compensation torque with an inverse dynamic feedforward torque, and converting the superposed torque into a current signal to drive a motor, thereby realizing high-dynamic and high-precision robust control under the physical boundary constraint.

The invention provides a motor protection circuit, a motor power supply system and electronic equipment, and belongs to the technical field of electronics. The motor protection circuit comprises an on-off control circuit; the on-off control circuit is connected with a three-phase inverter and a motor, and is used for disconnecting at least two phase current output ends of the three-phase inverter and the motor under the condition that the three-phase inverter has a control fault, so that an electrical connection loop does not exist between the three-phase inverter and the motor. The back electromotive force current generated by the motor due to the back electromotive force is effectively prevented from recharging through the three-phase inverter, and the problem that the three-phase inverter, the battery pack and other devices connected with the motor are damaged due to the back electromotive force current is solved.

The invention discloses an unmanned aerial vehicle power system sensorless control temperature identification method, and belongs to the technical field of motor control. The method aims at solving the problem that temperature identification in a permanent magnet synchronous motor driving system of an unmanned aerial vehicle depends on rotor position information, and closed-loop coupling contradiction exists between the temperature identification and rotor position estimation needed by sensorless control. Comprising the following steps: establishing a permanent magnet synchronous motor complex vector model based on extended back electromotive force in an estimated synchronous rotation gamma-delta reference system; establishing a full-order state sliding mode observer based on a complex vector by taking the stator current and the extended counter electromotive force as state variables; performing forward Euler discretization to obtain a full-order state sliding mode observer in a discrete domain, and observing a stator current estimated value and an extended back electromotive force estimated value; obtaining a rotor observation position and a rotor observation rotating speed; and designing an affine projection algorithm, identifying the stator resistance in real time in combination with a segmented regularization factor strategy, and estimating based on the stator resistance obtained by identification to obtain a motor temperature estimation value. The method is used for motor temperature identification.

The invention discloses a frequency adaptive position sensorless control method for a permanent magnet synchronous motor in the technical field of permanent magnet synchronous motors, and the method comprises the steps: adding an adaptive vector filter into an internal model of an extended state observer, so as to obtain an estimated counter electromotive force without phase lag; filtering third and fifth harmonics in the estimated counter electromotive force by using an adaptive vector filter; meanwhile, the motor rotating speed and the rotor position angle are estimated through an orthogonal phase-locked loop and are finally fed back to a vector control system; the frequency self-adaptive extended state observer can observe the back electromotive force under a relatively low bandwidth, so that the problem that bandwidth improvement and high-frequency noise filtering of the extended state observer cannot be considered at the same time is solved; according to the method, the frequency is adaptively changed along with the working frequency of the motor, so that the estimation precision of the counter electromotive force in a relatively wide rotating speed range is ensured, and high-performance position-sensorless control of the permanent magnet synchronous motor in the wide rotating speed range is realized.

The invention belongs to the technical field of motor control, and particularly relates to a motor three-phase counter electromotive force phase sequence detection circuit and a running direction judgment device. The phase sequence detection circuit comprises a comparison circuit and further comprises a tachogenerator coaxially connected with the motor to be detected, and the output end of the tachogenerator is electrically connected with the input end of the comparison circuit so that the phase sequence of the three-phase counter electromotive force of the motor to be detected can be obtained through the three-phase voltage output by the tachogenerator through the comparison circuit. The three-phase counter electromotive force of the to-be-tested motor is directly detected through the tachogenerator coaxially connected with the to-be-tested motor. The rotor of the tachogenerator rotates along with the rotation of the motor to be tested, and the rotor of the tachogenerator cuts magnetic lines in the operation process, thereby generating the three-phase counter electromotive force of the motor to be tested. The technical problem that in the prior art, when ground voltage detection is not accurate due to external interference, detected counter electromotive force is not accurate, and then the motor control effect is affected is solved.

The invention relates to the technical field of generator operation and maintenance, in particular to a permanent magnet generator short circuit fault monitoring and diagnosis method based on a diagnosis winding, which comprises the following steps: acquiring no-load back electromotive force signals in a normal operation state and various typical fault states of a permanent magnet generator, and constructing a normal feature data set and a fault feature data set; acquiring a no-load back electromotive force signal of the permanent magnet generator in the current operation state; comparing the obtained current no-load back electromotive force signal with the normal characteristic data set, and judging the current working state of the permanent magnet generator; if it is judged that the current working state of the permanent magnet generator is in the fault state, the obtained current no-load back electromotive force signal is compared with the fault feature data set. In combination with a data processing algorithm, the diagnosis winding can continuously monitor the operation state of the permanent magnet generator, compares the current operation parameters with the preset reference experiment data, accurately evaluates the health state of the winding, and monitors and diagnoses faults such as turn-to-turn short circuit in real time.

The invention relates to an optimal design method of a wind power controllable magnetic gearbox, and belongs to the field of wind power. The controllable magnetic gear box comprises an inner rotor, an outer rotor, a magnetism adjusting ring and a stator, an inner rotor average torque and torque pulsation, a stator no-load back electromotive force amplitude and a distortion rate are selected as optimization targets, ten parameters such as inner and outer rotor iron core thicknesses, a permanent magnet thickness, a magnetic adjusting ring thickness, a stator iron core outer radius and a stator winding turn number are selected as design variables to be optimized, an LHS experiment is carried out, and a BPNN proxy model is established and trained; performing Sobol 'global sensitivity analysis on the trained agent model to screen out key design variables to be optimized; optimizing the key design variables to be optimized by adopting NSGA-II to obtain an optimal solution set; and the optimal solution set is evaluated by adopting TOPSIS, and a group of optimal design variables are accurately selected, so that the optimization target is optimal. According to the method, the optimization precision and efficiency can be remarkably improved, and the purposes of reducing the cost and improving the performance are achieved.

The invention belongs to the technical field of direct-current synchronous motor control, and particularly relates to a PMSM improved sliding mode control system and method based on a two-section type dynamic boundary layer, in the aspect of rotating speed control, a rotating speed ring terminal sliding mode controller is introduced, related items of load torque and mechanical angular speed are combined into total disturbance, a nonlinear terminal sliding mode surface is selected, and the total disturbance is calculated. The problem that nonlinear disturbance cannot be effectively processed through traditional PI rotating speed control can be solved, finite time convergence of PMSM speed tracking errors is achieved, and meanwhile system buffeting is effectively reduced. In the aspect of current control, an improved sliding-mode observer is obtained according to a two-section quasi sliding-mode surface and an exponential reaching law design based on a terminal saturation function, so that the observation steady-state error of dq-axis back electromotive force is effectively eliminated, high-frequency buffeting in a sliding-mode reaching stage is effectively reduced, and the steady-state and dynamic performance of a system under electrical parameter mismatch is improved.

An electrically powered aircraft is configured to check the health of its motors by determining a flux linkage associated with each of the motors. The flux linkage may be determined by measuring the back-EMF of stator coils of the motor. The flux linkage may be measured while the motor is not powered or may be estimated when the motor is in use. The flux linkage of a motor may be compared to a corresponding threshold value to assess whether the magnet(s) of the motor have degraded to a point at which they pose safety concerns. The flux linkage values may also be used to project when the motor needs to be maintained and / or replaced. The flux linkage value of a motor may be displayed, along with historical flux linkage values for that motor, to show a magnitude of demagnetization of the magnet(s) of the motor.

The invention discloses an irreversible demagnetization risk prediction method for a permanent magnet synchronous motor, and the method comprises the steps: constructing a relation model between the temperature of a magnetic block and the no-load counter electromotive force of the motor, and calculating a target no-load counter electromotive force at a highest allowable environment temperature through employing a reference no-load counter electromotive force. According to the method, a complete physical relation chain from the magnetic block temperature to the residual magnetism density and then to the motor no-load magnetic flux and the motor no-load counter electromotive force is considered, the motor no-load counter electromotive force at the highest allowable environment temperature is obtained based on the relation model by using the reference no-load counter electromotive force to serve as the target no-load counter electromotive force, and accurate assessment of the irreversible demagnetization risk is achieved. In the running process of the motor, the no-load counter electromotive force of the motor is monitored when the motor driving current is zero and the motor is in the no-load running state every time, when the difference value between the target no-load counter electromotive force and the monitored no-load counter electromotive force exceeds a preset threshold value Eh1, early warning is triggered, and when the difference value exceeds Eh2, shutdown protection is triggered; risk monitoring of the magnetic performance state is achieved by indirectly monitoring the no-load back electromotive force.