483 results about "Shaft voltage" patented technology

The invention relates to the technical field of servo control, in particular to a high-precision current closed-loop control system and method for a servo driver, and the method comprises the steps: collecting three-phase current, rotor position, winding temperature and bus voltage, and constructing a state data set; constructing a parameter identification model fusing physical prior and an attention mechanism, deducing inductance and flux linkage parameters influenced by temperature, saturation and cross coupling, and correcting a motor model in real time; the correction parameters are injected into an FOC decoupling and feedforward link, and a self-adaptive PI regulator is linked to set the gain of a current loop on line; calculating a d-q axis voltage command according to the update model to respectively control excitation and torque components; an extended state observer is introduced to estimate load abrupt change and parameter disturbance, feed-forward compensation is carried out, and three-phase PWM is generated through anti-Parker and SVPWM; and an inverter nonlinear compensation model of a dead zone and switch delay is constructed, PWM is pre-distorted and output to a power device, and robust and low-ripple current closed-loop control of the servo motor is realized.

The invention belongs to the technical field of industrial control, and particularly relates to a brushless direct current motor high-efficiency control method and system based on an FOC algorithm, and the method comprises the steps: superposing high-frequency sine disturbance in a voltage instruction, extracting a response component, achieving the online identification of the equivalent impedance of a motor, and dynamically solving and updating the estimated values of resistance and inductance; and correcting d-axis and q-axis voltage feed-forward items in real time by using the updated parameters, and correspondingly adjusting a current loop proportion and an integral gain. The method can adapt to the time-varying characteristics of motor parameters in an industrial field, so that the accuracy of feed-forward compensation and the stability of current loop bandwidth are effectively guaranteed, and the robustness and the control precision of a control system under complicated industrial working conditions such as variable temperature and variable load are remarkably improved; and the requirements of high-end industrial equipment on high performance and high reliability of the motor driving system are met.

A system for measuring generator shaft voltage and shaft current, which system relates to the technical field of power systems. The system comprises a mounting component (100), which is used for mounting grounding carbon brushes (200) on a rotating shaft of a generator at the end that is close to an exciter and at the end that is close to a steam turbine, wherein the grounding carbon brushes (200) include a first grounding carbon brush (201) and a second grounding carbon brush (202) which are located at the steam turbine end of the generator, and a third grounding carbon brush (203) at the exciter end thereof; and by means of monitoring shaft voltage and shaft current in real time, a processing module (303) calculates key parameters and performs real-time analysis and spectrum analysis. When a monitored value exceeds a threshold value, the system immediately issues an alarm, thereby effectively realizing the real-time determination of the operating state of a generator and fault early warning. Moreover, the system has the functions of storing and querying historical data, by means of which operators can evaluate the insulation performance of a generator shaft and predict potential problems, and thus prevent insulation accidents caused by an overly high shaft current, thereby prolonging the service life of devices, and ensuring the continuity and stability of a power production process.

The invention discloses a VSG transient stability control method based on PSS power angle compensation and integral reactive loop cooperation, and the method comprises the steps: constructing an improved rotor motion equation compensation mechanism based on a power system stabilizer, and based on the dynamic parameters of the voltages vabc and pcc at a PCC point and the currents iabc and pcc flowing into the PCC point which are collected in real time, carrying out the compensation of the current iabc and pcc at the PCC point under the condition that the working condition is that the voltage of a power grid drops greatly. The dynamic characteristic of active power is ensured; constructing a PSS parameter optimization method based on zero point position constraint; an integral link is embedded in the traditional voltage-reactive droop characteristic, integral reactive loop control is constructed, and steady-state voltage deviation is eliminated; the output compensation power angle delta and the output voltage amplitude E are cooperatively applied and converted into dq-axis voltage components Ed and Eq, the dq-axis voltage components Ed and Eq are sent to a voltage and current double closed loop, a driving signal is generated through SVPWM, and the stability of the system is enhanced.

The invention provides a network construction control method and system for a static var generator without a super capacitor, and the method comprises the steps: obtaining a variable needed by the control of the static var generator, comprise a three-phase bridge arm voltage measurement value, a three-phase bridge arm voltage instruction value, a reactive power instruction value, an alternating voltage amplitude instruction value, an output reactive power measurement value, an output alternating current measurement value, an alternating voltage amplitude measurement value of a common coupling point, a direct-axis voltage measurement value and a quadrature-axis voltage measurement value; obtaining a three-phase modulation voltage through a voltage loop and an alternating current loop according to variables required by control and based on direct current voltage-frequency-phase control and reactive power-voltage droop control; and obtaining a switch tube control signal according to the three-phase modulation voltage, and completing network construction control of the static var generator according to the switch tube control signal. According to the invention, the stability of the DC voltage of the static var generator can be ensured without adding a super capacitor, and active support is provided for an AC side power grid.

The invention discloses a complex wave-based permanent magnet synchronous motor all-electrical parameter online identification method and device. The method comprises the following steps: analyzing the influence of a voltage error caused by dead zone time on parameter identification, and performing corresponding dead zone compensation; a bias complex wave with a certain amplitude and frequency is injected into the d-axis current, so that the d-axis current meets a parameter identification continuous excitation condition; constructing three groups of effective current slopes through four groups of different input data stored in the steady state of the motor, and identifying three groups of parameters of resistance, direct-axis inductance and quadrature-axis inductance by referring to a d-axis voltage equation and adopting a least square method with a forgetting factor; and finally, updating the identified three groups of parameters as known quantities in a q-axis voltage equation in real time, storing two groups of different input data to construct a group of effective current slopes, and identifying flux linkage parameters by adopting a least square method with a forgetting factor. According to the method, the under-rank problem of all-electrical parameter identification of the motor is solved, the identification precision is high, and the identification error of each parameter is about 3%.

The invention relates to an optimal power capturing method for a wave energy power generation device of a mixed-flow type air turbine, and belongs to the field of wave energy power generation. The optimal power capturing method comprises the steps that the change condition of the average output power of the turbine under different sea conditions along with the rotating speed is tested, and the maximum average output power point of the turbine under each sea condition is obtained; fitting the maximum average output power point under each sea condition to obtain a control law of the electromagnetic power of the motor; the quadrature-axis current reference value of the stator is made to be equal to zero, and the direct-axis current reference value of the stator is calculated; calculating a stator quadrature-direct axis current error term, and establishing a positive definite Lyapunov function; deriving the Lyapunov function, substituting the Lyapunov function into a stator quadrature-direct axis current state equation, and then performing transformation according to a first stability theorem to obtain a stator quadrature-direct axis voltage control law; and generating a corresponding SVPWM (Space Vector Pulse Width Modulation) switching signal according to a stator quadrature-axis voltage control law so as to control a motor-side converter and realize control on a turbine. The wave energy capturing efficiency can be improved.

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.

The invention discloses a self-adaptive field weakening control method for a permanent magnet synchronous motor, and the method comprises the following steps: 1, obtaining a difference value between a reference rotating speed and an actual rotating speed, and carrying out the PI operation of the difference value to obtain a reference current vector amplitude; 2, obtaining a difference value between the maximum reference torque angle and the current torque angle, carrying out PI operation on the difference value, and multiplying a PI operation result by the adaptive gain to obtain a compensation value of a reference current vector amplitude; 3, compensating the reference current vector amplitude through the compensation value to obtain an optimal reference current vector amplitude; obtaining a reference quadrature-axis current and a reference direct-axis current through the optimal reference current vector amplitude; 4, obtaining a reference quadrature-axis voltage and a reference direct-axis voltage, and carrying out amplitude limiting on the reference quadrature-axis voltage and the reference direct-axis voltage; and step 5, performing field weakening control on the permanent magnet synchronous motor according to the reference quadrature-axis voltage and the reference direct-axis voltage after amplitude limiting. According to the invention, low-development and high-reliability field weakening control can be realized.

The invention discloses a hybrid excitation synchronous motor control method and system, and belongs to the technical field of motor control. The problem that a motor control system can operate at high precision when a position sensor breaks down is mainly solved. The method comprises the following steps that when a position sensor breaks down, a system is switched to an active short circuit protection (ASC) mode, and operation of a motor is controlled by giving instruction values of d-axis current and q-axis current in the mode; then, in an ASC mode, estimating a rotor angle through a voltage equation in a static coordinate system, so as to obtain an electrical angle of a rotor; after the rotor angle estimation is completed, the system is switched from the ASC mode to the vector control mode without the position sensor, and the d-axis voltage and the q-axis voltage are adjusted in the mode, so that the motor can be continuously and accurately controlled and stably run. The invention provides an efficient and safe motor control method, and the safety and reliability of the electric vehicle under the condition of sensor fault are effectively improved.

The invention discloses a motor multi-parameter identification method based on sampling noise excitation and bias compensation, and the method comprises the steps: firstly obtaining the voltage and sampling current of a motor, and enabling the sampling current to comprise sampling noise; then constructing an information evaluation index, and adjusting a proportional parameter of a current controller to improve the identification information amount; then, shaft voltage feed-forward compensation is constructed to suppress electromagnetic torque pulsation; recursion is carried out by adopting a least square method based on the discrete linear parameterization model to obtain a parameter initial value and a covariance matrix; secondly, estimating offset-containing parameters on line, and calculating a sampling noise variance by using an estimated residual error; and finally, obtaining unbiased parameter estimation according to bias compensation iteration updating so as to output online estimation values of stator resistance, direct-axis inductance Ld, quadrature-axis inductance Lq and permanent magnet flux linkage.

The invention discloses a rotating speed fluctuation suppression method and an operation control device of a permanent magnet synchronous motor, and relates to the technical field of permanent magnet synchronous motor control, and the method comprises the steps: obtaining a q-axis current feedback signal, a d-axis current feedback signal, a q-axis current reference signal and a d-axis current reference signal; a d-axis voltage reference signal is obtained according to the d-axis current reference signal and the d-axis current feedback signal, a first q-axis voltage reference signal and a second q-axis voltage reference signal are obtained according to the q-axis current feedback signal and the q-axis current reference signal, and a q-axis voltage reference signal is obtained according to the first q-axis voltage reference signal and the second q-axis voltage reference signal; the first q-axis voltage reference signal and the second q-axis voltage reference signal are obtained through different controllers; and generating a PWM control signal according to the q-axis voltage reference signal and the d-axis voltage reference signal. The method has the effect of effectively improving the rotating speed fluctuation suppression effect of the permanent magnet synchronous motor.

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 discloses a method and a system for estimating direct-current bus current of an electric vehicle. The method comprises the following steps: acquiring a d-axis voltage instruction, a d-axis current, a q-axis voltage instruction and a q-axis current of a motor side; compensating the d-axis voltage instruction and the q-axis voltage instruction based on parameters including voltage delay time to obtain a compensated voltage value; calculating the electromagnetic power of the motor based on the compensated voltage and current; the loss power of hardware in the motor controller is obtained, and the direct current side power is calculated in combination with the electromagnetic power; and calculating a direct current bus current estimation value based on the direct current bus voltage and the direct current side power. According to the method, processing is carried out under the dq coordinate system, the operation requirement of the controller is reduced, the power calculation error is corrected through voltage compensation and system loss compensation, high-precision and low-cost direct current bus current estimation is achieved under the condition that an additional hardware sensor is not needed, and the control precision and reliability of an electric drive system are improved.

The invention relates to the technical field of motor control, and discloses a motor optimization control method and system based on q-axis voltage control, and the method comprises the steps: carrying out the Clark-Park conversion and sliding mode observation of a three-phase current signal and a three-phase voltage signal, and obtaining a d-axis current signal, a q-axis current signal, a d-axis flux linkage component and a q-axis flux linkage component; performing recursive least square identification processing to obtain a real-time salient pole ratio value; reluctance torque angle arc tangent calculation and d-q axis coupling quantity product operation are carried out to obtain reluctance torque coupling disturbance quantity; according to the method, the limitation that in the prior art, work is only carried out near an MTPA curve is broken through, the adverse effect of d-q-axis cross coupling on q-axis voltage control precision is effectively eliminated, and the control precision of the q-axis voltage is improved. And the torque output capability and the dynamic response performance of the motor under various working conditions are improved.

The invention discloses an SOP and feeder automation cooperative local fault self-healing method and system, relates to the field of distribution line fault self-healing, and can enable a section switch to lose voltage without opening when an interphase short circuit fault occurs in an SOP-containing distribution line, and firstly starts a fault current-limiting control measure to enable the fault to extinguish arc; secondly, a detection signal is injected in a fixed d-axis voltage mode, and permanent fault recognition is carried out; and finally, on the basis of a fault property identification result, constructing an SOP and feeder automation cooperative local fault self-healing scheme. The method can effectively discriminate the fault property and accelerate the power recovery speed, and facilitates the improvement of the power supply reliability of a power distribution system.

To provide a sealing material with a simple structure that can discharge (divert) current flowing through a rotation axis such as a shaft due to shaft voltage to the outside, and that also exhibits excellent wear resistance.SOLUTION: The invention provides a sealing material made of a fluororesin base material and including at least an annular base portion. The base portion has a low-conductivity portion with a volume resistivity of 1.0×104 Ω cm, and a high-conductivity portion having a lower volume resistivity than the low-conductivity portion. The high-conductivity portion is formed at least at one location in the circumferential direction of the base portion.SELECTED DRAWING: Figure 1

The invention discloses a rotor turn-to-turn short circuit diagnosis method based on an exciting current-shaft voltage harmonic nonlinear correlation coefficient. The method comprises the following steps: synchronously collecting parameters, and preprocessing the collected parameters through wavelet threshold denoising and temperature normalization; extracting harmonic analysis according to the shaft voltage harmonic characteristics; identifying magnetic saturation, temperature and load nonlinear factors and calculating corresponding coefficients; performing dynamic correction on the Pearson's correlation coefficient through the nonlinear correction coefficient, and combining with fuzzy logic weighting to obtain fuzzy logic weighting; defining a working condition feature vector, and constructing a working condition adaptive dynamic model comprising a linear regression basic model and an LSTM neural network; and calculating a dynamic threshold value based on the basic threshold value and the nonlinear factor, and judging the turn-to-turn short circuit trend of the rotor according to the comparison of the correlation coefficient and the dynamic threshold value and a prediction result. According to the invention, through combination of the nonlinear correction correlation coefficient and the LSTM neural network, dynamic compensation of nonlinear factors is realized, and the accuracy and reliability of rotor turn-to-turn short circuit fault diagnosis are improved.

A method is for adaptively controlling a charging module that converts three-phase AC input to DC output with improved power factor correction. The method includes performing Clarke and Park transforms on input three-phase AC voltages to obtain d-q axis components, measuring and transforming boost inductor currents to obtain current axis components, generating control values through current-loop and voltage-loop modules based on target and measured values, and synthesizing PWM signals to control switching operations. The method features adaptive phase angle computation using a proportional-integral controller that responds to load variations in real-time. The control system maintains high power factor under varying load conditions by continuously adjusting the phase reference based on the q-axis voltage error. This approach minimizes power losses, reduces harmonic distortion, and ensures stable operation across the full operating range of the charging module while maintaining unity power factor.

The application discloses a multi-port impedance optimization-based harmonic suppression method for a non-electrolytic capacitor permanent magnet synchronous motor driving system, and belongs to the technical field of motor control. The application is aimed at the problem that active damping control will cause the increase of machine-side harmonics when used for the network-side current harmonic suppression of a non-electrolytic capacitor motor system. The machine-side port impedance regulation voltage and the network-side port impedance regulation voltage are calculated. The entropy weight TOPSIS method is used to calculate the optimal angle of the machine-side and network-side port impedance regulation voltage, and the machine-side and network-side port impedance regulation voltage is synthesized into a cooperative voltage. The cooperative voltage is decomposed into a d-axis component and a q-axis component, and then is superimposed on the dq-axis voltage given value, so that the controlled dq-axis voltage given value is obtained. The regulated alpha-beta axis voltage given value is obtained through the inverse Park transformation link, and then the pulse control signal of the inverter is obtained through the SVPWM control, so that the machine-side and network-side harmonic suppression of the driving system is realized. The application is used for the cooperative suppression of machine-side and network-side harmonics.

A carbon brush holder structure capable of being used for measuring voltage and current of a hydro-generator shaft comprises a generator shaft shell, a brush holder structure is arranged on the generator shaft shell, and a carbon brush is installed on the brush holder structure. The brush carrier structure comprises a mounting base and a mounting column, the mounting base is provided with a plurality of fixing holes and a limiting sliding base, fastening bolts connected with a generator shaft shell are arranged in the fixing holes, a movable base is arranged on the limiting sliding base, and the mounting column matched with a carbon brush is arranged on the movable base. With the adoption of the structure, the mounting seat of the brush carrier structure is made of metal and can be welded or fixed with a fixed part through screws, and reliable strength is ensured; the insulating rod and the carbon brush holder can be tightly fixed together and are insulated from the base; the whole device is simple in structure, convenient to adjust front and back, stable in supporting and convenient to accurately adapt to measurement work.

The invention provides a device for testing the shaft voltage in bearing electrocorrosion, which comprises a rotating shaft, a pair of bearings is mounted on the rotating shaft, one end of the rotating shaft is connected with a servo motor through a magnetic coupling, the servo motor is connected with a frequency converter, the rotating shaft is connected with a function signal generator, and the function signal generator is connected with a signal generator. The voltage measuring point of the bearing is connected with an oscilloscope, an adjustable resistor is connected in series between the voltage measuring point of the outer diameter of the bearing and the oscilloscope, and the oscilloscope is in communication connection with an upper computer through a data switch; based on the device, on the second aspect, the invention provides a method for testing and analyzing the shaft voltage in bearing electro-corrosion, a corresponding recognition algorithm is designed according to the data collected by the oscilloscope and a bearing capacitor discharge event, and then the bearing electro-corrosion is identified through the applied common-mode voltage and the measured shaft voltage. And bearing capacitance, breakdown voltage, discharge energy and discharge times are calculated, so that data support is provided for subsequent motor bearing fault prediction and life evaluation.

The invention discloses a model-free predictive control method and system for a permanent magnet motor with an embedded generalized integral observer, and belongs to the field of permanent magnet motor control. A hyper-local model of the permanent magnet motor is constructed, disturbance variables of mechanical angular velocity and q-axis current are integrated to form lumped disturbance by introducing a new variable, and model reconstruction is performed to obtain a model-free predictive control model of the permanent magnet motor; observing disturbance of the reconstructed model through a third-order extended state observer embedded with a quasi-second-order generalized integrator to obtain a rotating speed prediction model; observing disturbance on the d-axis current model through an observer to obtain a d-axis current prediction model; based on the two prediction models, establishing a control rate equation of the d-axis voltage and the q-axis voltage; and based on the acquired system parameters, through a control rate equation, voltage of d and q axes is calculated to control motor driving. By integrating the disturbance of the rotating speed outer ring and the q-axis current ring into lumped disturbance, the design cost is reduced, and the dynamic response is improved. Through the TESO architecture embedded with the QGI, both dynamic disturbance rejection and periodic disturbance suppression are considered, and the stability of the system is guaranteed.

A measuring device for large shaft current and large shaft voltage of a hydraulic turbine set comprises a large shaft and a rotor, and further comprises a fault wave recording device and a first insulation brush holder arranged above the rotor, the fault wave recording device is provided with a voltage measuring winding, the first insulation brush holder is provided with a first carbon brush, one end of the first carbon brush is connected with the large shaft, and the other end of the first carbon brush is connected with a second carbon brush. The first carbon brush is connected with one end of a voltage measuring winding through a first cable, and the other end of the voltage measuring winding is grounded. The utility model is used for solving the problems that the fault of the large shaft insulation monitoring CT cannot be eliminated and the actual shaft voltage and the actual shaft current of the large shaft cannot be directly monitored in the existing shaft CT monitoring mode.

The invention discloses a whole vehicle electric drive resolver zero position identification and whole vehicle electric drive resolver zero position self-inspection method, and relates to the field of new energy electric drive control systems.The whole vehicle electric drive resolver zero position identification method comprises the steps that a direct-axis current instruction and a quadrature-axis current instruction are generated by receiving a torque instruction of a whole vehicle controller; sampling a motor phase current and performing coordinate transformation to obtain a feedback current; inputting the current instruction and the feedback current into a current regulator, and outputting direct-axis and quadrature-axis voltage components; injecting a high-frequency square-wave voltage signal into the direct-axis voltage component to generate a synthesized direct-axis voltage component, and performing PWM (Pulse-Width Modulation) to generate a driving signal; sampling the phase current again, extracting the high-frequency quadrature-axis response current, calculating the rotor position deviation, and inputting the rotor position deviation into the position observer to obtain the absolute position information of the rotor; wherein the PWM wave sending time sequence is aligned with the phase current sampling time sequence. According to the invention, the precision and efficiency of whole vehicle electric-drive rotary transformer zero position identification can be improved.

The invention discloses a method and device for distinguishing an internal fault from an external fault, and the method comprises the steps: obtaining the real-time voltage of a power transmission line after the fault, carrying out the processing of the real-time voltage of the power transmission line after the fault through a low-pass filter, and obtaining the real-time voltage of the power transmission line which is linearly distributed along the line, the method comprises the following steps: for real-time voltage of a power transmission line which is linearly distributed along the line, converting three-phase voltage from an abc coordinate system to a dq coordinate system by utilizing dq conversion, obtaining d-axis voltage variation of a fault point F and a setting point S after the dq conversion, and judging whether the fault is an internal fault or an external fault based on the d-axis voltage variation of the fault point F and the setting point S. According to the method and the device provided by the embodiment of the invention, the internal and external faults can be distinguished.

To provide a method for estimating an axis error between a d-q axis and a γ-δ axis in a synchronous motor.SOLUTION: In a control method for driving a synchronous motor by sensorless vector control, a magnetic axis of a permanent magnet of the synchronous motor is defined as a d-axis, a direction orthogonal to the d-axis is defined as a q-axis, a designated magnetic axis of the synchronous motor is defined as a γ-axis, and a direction orthogonal to the γ-axis is defined as a δ-axis, and when vγ iγ+vδ iδ=P / 2 ωR ΦM iδ+R (iδ^2+iγ^2) is established, it is estimated that the d-q axis and the γ-δ axis coincide with each other without an error, and when the above expression is not established, an amount of the error is estimated from a difference between the left side and the right side. vγ represents a γ-axis voltage [V], iγ represents a γ-axis current [A], vδ represents a δ-axis voltage [V], iδ represents a δ-axis current [A], P represents a motor pole number, R represents a motor one-phase resistance value [Ω], ωR represents a motor electrical angular speed [rad / s], and ΦM represents a magnet flux [wb].SELECTED DRAWING: Figure 2

The present disclosure relates to an electric motor assembly configured to mitigate electrically induced bearing damage (EIBD). More specifically, the electric motor assembly includes a chassis, a stator, a winding coil, a rotor, a shaft, conductors, a circuit, and insulators. The circuit can include one or more transformers capable of generating an injection voltage, which can mitigate shaft voltages that cause EIBD.

The application discloses a kind of static excitation generator shaft voltage component analysis method and device, the method is applied to generator, the method includes: measuring the shaft voltage component parameter of generator under different measurement state;Whether the shaft voltage component parameter reaches dangerous value is detected;If yes, then output classification alarm.The device includes rotor body, one end of the rotor body is steam end large shaft, the other end of the rotor body is excitation end large shaft, steam end carbon brush is connected on the steam end large shaft, excitation end carbon brush is connected on the excitation end large shaft, shaft voltage suppressor is connected on the excitation end carbon brush, the steam end carbon brush and the shaft voltage suppressor are electrically connected with relay.The application adopts the above method, with the advantages of high measurement accuracy, sensitive and effective, high degree of automation, guide repair.

The present invention proposes a position sensorless predictive control method and system for a permanent magnet synchronous motor, relating to the field of motor control technology. The method comprises calculating the d- and q-axis voltages and d- and q-axis currents of the motor; using the q-axis stator current observation value, the motor speed observation value, and the load torque observation value as state variables, and the q-axis stator current error as feedback, to determine the observed value of the motor speed; calculating the motor stator current based on the observed value of the motor speed; using the total unknown part of the motor system and the motor stator current as state variables, and the current observation error as feedback, to determine the αβ-axis stator current values ​​of the motor; and obtaining the desired stator voltage value based on the αβ-axis stator current values ​​of the motor, thereby controlling the motor using the desired stator voltage value. The present invention can effectively improve the observation accuracy and the anti-disturbance capability of the control system, and combines position sensorless control with predictive control to effectively improve the dynamic characteristics of the control system.