79 results about "Pi regulator" 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 discloses a specific grid-connected current harmonic suppression method and device for an energy storage converter, and belongs to the technical field of power systems, and the method comprises the steps: obtaining a given current value of a fundamental current loop, and carrying out the dq / abc conversion to obtain a three-phase current reference value; acquiring a three-phase current value of a power grid side, and subtracting the three-phase current value from the three-phase current reference value to obtain a harmonic current value; converting the harmonic current value to a target subharmonic synchronous rotating coordinate system to obtain a target subharmonic current value; extracting the target sub-harmonic current value in a direct current form through a low-pass filter, and sending the target sub-harmonic current value to a PI regulator for regulation to obtain a harmonic voltage compensation amount; and injecting the harmonic voltage compensation amount into a modulation wave to realize suppression of the target subharmonic current. According to the invention, the grid-connected side current harmonic of the energy storage converter can be effectively suppressed, and the grid-side current quality is improved.

The invention discloses a network construction type converter pre-synchronization control method based on Taylor compensation, and the method comprises the steps: collecting the three-phase voltage of an output end of a virtual synchronous generator (VSG) and the three-phase voltage of a power grid side, carrying out the Clark transformation, and extracting a positive sequence voltage component; on the basis of the positive sequence voltage component, calculating a phase difference sine value of the VSG output voltage and the power grid voltage; based on the phase difference sine value, compensating the phase difference sine value through Taylor expansion to obtain a compensated real-time phase difference; and fusing the compensated real-time phase difference into a VSG phase-locked loop-free pre-synchronization control strategy, and driving a PI regulator to dynamically correct the output frequency and phase of the VSG. A phase-locked loop is completely abandoned, and the frequency oscillation risk is eliminated; expanding a phase difference calculation range through third-order Taylor compensation; voltage vector analysis and a dynamic compensation function are fused, phase synchronization is achieved, and grid-connected impact current is reduced.

The invention relates to the technical field of motor control, and discloses a vector control application of a direct drive motor, which comprises the following steps: S1, collecting stator current, rotor speed and bus voltage signals of the motor, and carrying out filtering preprocessing on the collected signals; and S2, constructing a self-adaptive flux linkage observation model, estimating a stator flux linkage in real time based on stator current and bus voltage signals in combination with rotor rotating speed information, and correcting stator resistance and inductance parameters through a model reference self-adaptive algorithm. According to the method, the motor parameters are corrected in real time through the self-adaptive flux linkage observation model, parameter drift caused by factors such as temperature change and magnetic saturation is effectively counteracted, and the accuracy of flux linkage estimation is improved; the improved PI regulator realizes online self-tuning of control parameters through a fuzzy control algorithm, can quickly adapt to changes of dynamic characteristics of the motor, and shortens the regulation response time of flux linkage and torque; and the resistance of the system to external interferences such as load fluctuation, power supply voltage change and the like is enhanced.

The invention relates to the technical field of battery energy storage, and discloses a centralized energy storage system and a battery equalization method, and the system comprises a plurality of battery clusters which are connected in parallel, and power branches are converged to a high-voltage DC bus; the battery management system is used for acquiring and respectively calculating average values based on the charge state parameters and the current parameters; the battery equalizer is arranged in the power branch; the balance control unit is used for determining a current control reference value of each battery cluster according to each obtained numerical value, and a difference value between the current control reference value and a current parameter of the corresponding battery cluster is used for being input into a PI regulator and is used for outputting a voltage regulating variable to be superposed with an initial output voltage to form an output voltage reference value; wherein the battery equalizer is configured to adjust the output voltage according to the output voltage reference value, so that the current parameter tracks the current control reference value, the dynamic equalization of the SOC is realized, and the difference of the available power of each battery cluster is reduced or even kept consistent before the available power reaches a full or emptying state.

The invention discloses a permanent magnet synchronous motor wide speed range model prediction control method and system based on a mean value reduction optimization algorithm, and belongs to the technical field of motor control. According to the method, a discrete mathematical model of the permanent magnet synchronous motor is established under a d-q rotating coordinate system, a q-axis current reference value is generated by an outer ring through a speed PI regulator, and a d-axis current reference value is calculated in combination with a maximum torque per ampere (MTPA) principle and a weak magnetic region voltage constraint; finite control set model prediction control is adopted in an inner ring, enumeration prediction is conducted on candidate voltage vectors of the three-phase voltage source type inverter, a cost function containing a d-axis current error, a q-axis current error and an electromagnetic torque error is constructed, an optimal voltage vector is selected, and a three-phase PWM signal is generated through space vector pulse width modulation to drive a motor. The system is provided with a mean value reduction optimization module, joint optimization is carried out on speed outer ring PI parameters and cost function weight coefficients in the off-line stage, the parameters are stored in a lookup table, and automatic setting of control parameters is achieved. The permanent magnet synchronous motor can improve the dynamic response performance of the rotating speed and the current in the base speed area and the weak magnetic area, reduce the total harmonic distortion of the stator current, improve the voltage utilization rate and the overall operation efficiency of the permanent magnet synchronous motor, and is suitable for occasions such as electric vehicle driving and high-performance servo systems.

The invention discloses a photovoltaic power generation control system, a control method, equipment, a medium and a product, and relates to the technical field of photovoltaic power generation, in the control system, the working mode of a photovoltaic array is determined through a front-stage DC / DC control module according to the maximum available power of the photovoltaic array, the actual output power of the photovoltaic array and the power of the power grid side; the pulse duty ratio is adjusted according to the working mode of the photovoltaic array, and a pulse width modulation signal is generated to control the DC-DC boost converter; transient power suppression is carried out through a post-stage DC / AC control module according to power grid side power and actual output power of a photovoltaic array, direct-current bus extra reference voltage is generated, and PI adjustment is carried out according to the direct-current bus reference voltage and an error value between the direct-current bus extra reference voltage and the direct-current bus voltage. And according to a result output by the second PI regulator and a voltage phase signal, a voltage signal and a current signal of a power grid side, a space vector pulse width modulation signal is generated to control the DC-AC inverter, so that efficient, stable and intelligent management of photovoltaic power generation is realized, and powerful technical support is provided for wide application of photovoltaic energy.

The application relates to a kind of linear vernier permanent magnet motor deadbeat control methods, on the basis of traditional DTC control, by introducing speed backstepping controller to replace traditional speed loop PI regulator, using deadbeat controller to replace current loop PI regulator, using improved double-sampling double-update SVPWM to replace traditional SVPWM modulation module.According to multiple simulation, the application can effectively reduce the overshoot of the system and effectively reduce the thrust ripple of the system on the basis of maintaining traditional DTC control, and improve the dynamic performance of the system.

The application discloses a five-seventh harmonic suppression method suitable for a twelve-phase motor, four sets of three-phase currents of a twelve-phase propulsion system are collected to obtain twelve alternating currents; two sets of three-phase windings of the twelve-phase motor with a phase difference of 30 degrees are taken as a whole, five-seventh harmonic amounts of the two sets of three-phase currents with a difference of 30 degrees are converted into direct currents by using a six-phase park conversion matrix; the output amounts of the direct currents obtained by a PI regulator are combined with the direct currents on a fundamental wave plane, and the alternating currents calculated by using a six-phase park inverse conversion matrix are taken as corresponding modulation waves of each channel respectively. The application is simple and easy to implement, has strong universality, has good five-seventh harmonic suppression effect, and is easy to be popularized to other multi-phase motor system harmonic suppression occasions.

The application discloses a kind of control circuit and method of server standby power supply, including main power drive unit, analog PI regulator, current sampling conditioning circuit and OringFET tube;Main power MOS tube realizes main loop on-off control, and triode is used to change the gate voltage of main power MOS tube to control its conduction, cut-off;Analog PI regulator is composed of reference source and operational amplifier, reference source provides accurate reference voltage, and operational amplifier compares and adjusts current detection signal with reference voltage, dynamically corrects the control level signal of output, and then controls the on-off of main power MOS tube through driving circuit;Current sampling conditioning circuit includes sampling resistance and differential amplifier, and real-time acquisition main loop current is converted into identifiable voltage signal, to provide accurate data support for analog PI regulator.The application is applied when server is in shutdown state, and can be remotely executed by network to start, restart, install operating system or monitor hardware health state and the like operation.

The invention discloses a PI regulator with a leakage compensation function and a null drift suppression method thereof.According to the PI regulator, a leakage observer and a leakage PI compensator are embedded in a classic PI regulator, the leakage observer executes a real-time leakage flow estimation algorithm and inputs the estimated real-time leakage flow into the leakage PI compensator, and the leakage PI compensator and the leakage observer are connected in sequence. The leakage PI compensator calculates leakage compensation current according to the real-time leakage flow and inputs the leakage compensation current into the adder, the adder adds the output control signal and the leakage compensation current to obtain a control current instruction, and the control current instruction is input into the servo amplifier and controls displacement of the oil cylinder through the servo valve. According to the method, a leakage observer and a leakage PI compensator are used for calculating leakage flow and leakage compensation current, saturation judgment and current amplitude limiting are executed, and corresponding leakage compensation current is output. According to the PI regulator and the zero drift suppression method thereof, oil cylinder position drift is greatly reduced, zero return overshoot is completely eradicated, manual calibration is canceled, one-time calibration is effective for a long time, and the equipment cost is reduced.

The invention discloses an ultrasonic motor driving control strategy based on voltage amplitude-frequency hardware decoupling. Phase voltage, phase current and rotation angle signals of a motor are sampled through a sensor and an encoder, a voltage and current phase difference is obtained by adopting a zero crossing point detection method, resonant frequency is obtained by combining a PID frequency regulator, and independent frequency control is realized by matching with a fixed duty ratio; the rotating speed is obtained through differential operation, reference voltage is obtained through a PI regulator, and independent amplitude control is achieved by combining a voltage amplitude obtained through a rectification average value method with a PID voltage regulator and matching with a fixed frequency. The two-stage circuit topology is adopted to independently regulate and control the voltage amplitude and the voltage frequency, the problems that voltage amplitude regulation is nonlinear and voltage frequency regulation is coupled in a traditional ultrasonic motor driving scheme are solved, the voltage amplitude is independently regulated at the front stage, the voltage frequency is independently regulated at the rear stage, hardware decoupling of the voltage amplitude and the voltage frequency is achieved, and the system reliability is improved. The harmonic content of the output voltage of the driving circuit is lower, and the voltage control is more linear.

The invention discloses a single-phase dual-active bridge micro-inverse controller with preset internal phase shift and external phase shift in the technical field of power electronics and electricians. A power grid voltage phase-locked loop obtains a phase signal of power grid voltage; generating an inner phase shift angle and an outer phase shift angle preset quantity by the inner phase shift preset law and the outer phase shift preset law; a grid-connected current peak value output by the MPPT voltage loop is multiplied by a power grid voltage phase signal generated by the power grid voltage phase-locked loop to obtain a grid-connected current given value, a current PI regulator of the grid-connected current loop generates an external phase-shift angle compensation amount of a corresponding switch tube, and the external phase-shift angle compensation amount is superposed with an external phase-shift angle preset amount to obtain an external phase-shift angle of the corresponding switch tube; the internal phase shift angle and the external phase shift angle are sent to a phase shift controller to generate phase shift pulse control signals corresponding to on-off of a switching tube in the single-phase dual-active bridge micro inverter, power generation of photovoltaic energy to a power grid is realized, stable adjustment of the single-phase dual-active bridge micro inverter is facilitated, and the response speed of the system is improved.

The application relates to a rolling mill calendering roller flattening force control method, characterized by the following specific steps: step S1, hardware improvement: angle encoders are installed on the swing arm pivot fulcrums of the driving side and the operating side of the rolling mill calendering roller, swing arm angles of the driving side and the operating side are collected in real time, step S2, mathematical model construction: a model is established based on the swing arm angle data, and step S3, PI closed loop control; the application compares the actual force (T dact , T Oact measured by a pressure sensor) of the hydraulic cylinder with the given force (T dref , T Oref ), calculates the deviation (Delta T d , Delta T O ), dynamically adjusts the input current of the proportional valve of the hydraulic cylinder on the two sides through a PI regulator, compensates the deviation in real time, ensures that the flattening forces (F d , F O ) on the two sides are consistent, and thus the unbalance of the forces on the two sides caused by mechanical wear and installation errors can be eliminated, and defects such as one-side waves and layering can be inhibited.

Methods, systems, and apparatuses for improved torque ripple compensation for motors experiencing torque ripple are provided. For example, a method of torque ripple compensation includes receiving a speed difference signal associated with a difference between a motor speed and a reference speed. Then generating a torque compensation signal by: generating, via an α-β construct, one or more α-β signals based on the speed difference signal; converting, via a Park transform, the α-β signals to one or more transformed signals; filtering the transformed signals with one or more low pass filters to provide one or more filtered signals; regulating, via one or more PI regulators, the filtered signals to provide one or more regulated signals; converting, with an inverse Park transform, the regulated signals to a torque compensation signal. Then control a motor based at least on the torque compensation signal.

The application provides a four-wheel drive four-wheel steering robot chassis control method based on a dynamic LQR, and belongs to the technical field of robot chassis motion control. The method comprises a PI regulator 1, a PI regulator 2, an LQR regulator and a robot four-wheel steering mode dynamics model. The robot four-wheel steering mode dynamics model is established, and the dynamics model comprises a robot four-wheel steering mode lateral dynamics model and a robot four-wheel steering mode yaw dynamics model. The lateral and yaw dynamics models are converted into state space expression forms. According to the modern control theory, a control performance index function is established, a real-time feedback adjustment control parameter matrix is adjusted, LQR control performance is optimized, and a full-closed-loop parameter control is formed. The dynamic control of the LQR is realized according to the current chassis motion state, and the control performance and adaptability are further enhanced.

The invention discloses a harmonic extraction method and device based on an improved orthogonal phase-locked loop, a terminal and a medium, and the method comprises the steps: collecting a three-phase voltage signal, and carrying out the preprocessing of the three-phase voltage signal; calculating the frequency fluctuation quantity according to the fundamental frequency tracked by the orthogonal signal generator; based on the damping coefficient, processing the preprocessed signal through an orthogonal signal generator to generate an orthogonal signal; carrying out notch suppression on the preprocessed signal and the orthogonal signal, and optimizing a damping coefficient; park transformation is carried out on the preprocessed signals and orthogonal signals, and fundamental wave parameters are output through a PI regulator; configuring a central angular frequency for each to-be-extracted harmonic component based on the fundamental wave parameter, and calculating a harmonic amplitude and a phase; through the improved orthogonal signal generator, the fundamental wave phase locking anti-interference performance is improved, the fundamental wave phase locking error is reduced, and extraction deviation caused by frequency fluctuation is avoided.

The application discloses a hybrid energy storage system energy management method and system, and relates to the technical field of energy storage system energy management. The method comprises the following steps: collecting output currents of each energy storage converter and estimating physical link impedance values of each converter branch to a DC bus; constructing a physical link decoupling term and superimposing the physical link decoupling term into a droop control model to generate a preliminary voltage reference value; collecting output voltages of each energy storage converter after physical link decoupling, inputting the output voltages into a PI regulator respectively after being subtracted from a set DC bus voltage reference value, calculating a battery-side virtual voltage source compensation term and a super capacitor-side virtual voltage source compensation term, and performing second correction on the preliminary voltage reference value to obtain a final output voltage reference value; and sending the final output voltage reference value into a voltage-current double closed loop controller for modulation to generate a PWM driving signal, so as to control actions of each energy storage converter. The method eliminates high-frequency fluctuation components of the bus voltage under high-frequency and severe fluctuation of the load, and ensures stability of the bus voltage.

The invention belongs to the technical field of power electronic equipment, and particularly provides an active damping constant-power control method for a common-high-frequency-link direct-current transformer and a medium, and the method comprises the steps: firstly obtaining a port direct-current side current i2 at a constant-power operation mode port of the common-high-frequency-link direct-current transformer; in the active damping constant-power controller, port direct-current side current i2 at a constant-power operation mode port is used as input, and an output value yc is obtained after the port direct-current side current i2 passes through an active damping unit; after the port current error ei2 passes through a PI regulator, an output value yc of the active damping unit is superposed to obtain an intermediate quantity yd; and finally, amplifying the intermediate quantity yd through a gain amplification unit to generate a phase shift ratio d2 of the constant-power operation mode port, and outputting the phase shift ratio d2 to the constant-power operation mode port to control the constant-power operation mode port to operate. According to the scheme, on the premise that the actual line resistance is not additionally changed and the loss is not increased, the operation stability of the common-high-frequency-link direct-current transformer can be effectively improved, and low-frequency oscillation is restrained.

The invention discloses a network construction type photovoltaic converter robustness enhancement control method based on dual-channel super local modeling, and the method comprises the steps: 1) enabling a voltage outer ring to construct a super local model-free prediction model by taking a capacitor voltage as an object, carrying out the online estimation of the dynamic disturbance of a system through a sliding mode disturbance observer, and generating a target inductive current instruction; and 2) receiving the instruction by a current inner ring, constructing a super-local model-free prediction model of the inductive current, estimating disturbance on line by adopting a multi-step sliding mode difference method, predicting current change based on a candidate voltage vector, and selecting a switch state. The inner ring and the outer ring are separated, the structure is clear, and decoupling performance is good; the two channels do not depend on specific circuit parameters, and the robust stability under parameter uncertainty is remarkably improved; a traditional PI regulator is not needed in the whole process, the design is simplified, the anti-interference capability and the dynamic response speed are enhanced, and the method is suitable for a high-reliability and high-performance network-building type photovoltaic converter system.

The application discloses a three-phase grid-connected converter control method, a circuit, a device and a medium, and relates to the technical field of AC-DC power distribution systems. The three-phase grid-connected converter control method provided by the application establishes a mathematical model of the three-phase grid-connected converter, combines the causes and suppression mechanism of the leakage current, controls the filter capacitor voltage in the zero sequence loop to be a constant value through a PI regulator, and effectively attenuates the leakage current. The phase angle of the grid voltage is obtained in a three-phase stationary coordinate system, the sampling quantity is coordinate-transformed according to the angle, a modulation signal is obtained, and the power switch tube in the grid-connected converter is controlled according to the modulation signal. Since only one connected wire needs to be added between the middle point of the filter capacitor and the common point of the lower bridge arm in the scheme, the cost is low, and the leakage current caused by the existence of the parasitic capacitance of the DC side power distribution device to the ground can be limited to the microampere level.

The application discloses a single-phase control system and method based on d-q rotating coordinate transformation, adopts a double-loop architecture of a voltage outer loop and a current inner loop, the voltage outer loop filters a sampling voltage through a second-order generalized integrator, obtains d-q axis voltage components through Park transformation, and generates a d-axis current reference value by using a PI regulator; the current inner loop also filters and transforms the sampling current, inputs a current error into a PI regulator to obtain a current compensation component, eliminates the coupling influence between d-q axes through decoupling operation, and finally generates a duty cycle signal for driving an inverter through inverse coordinate transformation. Through the double-loop cooperative control and decoupling algorithm, the application realizes high-precision voltage stabilization of the inverter output voltage and fast dynamic response of the current, effectively suppresses harmonics and load disturbance, and improves the output power quality.

The invention discloses a multi-machine control method and equipment based on a high-frequency ripple adjustable electrolytic hydrogen production test power supply, and relates to the field of electrolytic hydrogen production power supply control. Based on a single-closed-loop direct load current control strategy, feedback control is performed on the load current of the test power supply, and a current error is calculated; filtering and adjusting the current error by using a notch filter and a PI regulator, and calculating to obtain an intermediate voltage through a multi-machine proportionality coefficient module; the intermediate voltage is input to a PWM adjusting circuit to generate a driving pulse; and carrying out multi-machine control on the multi-machine parallel Boost conversion circuit in a wide working condition range by using a driving pulse. The high-precision output of the broadband adjustable high-frequency ripple current for the electrolytic hydrogen production load test is realized, the resonance peak is effectively suppressed, the nonlinearity is weakened and the linear working interval is widened through the single closed-loop direct current control and virtual impedance strategy, and the extra loss is avoided while the precision of a multi-machine parallel system is ensured.

The invention provides a self-adaptive damping control method of a bidirectional direct-current converter under a load throwing working condition, and relates to the field of power electronics, and the method comprises the steps: building a bidirectional direct-current converter system, collecting circuit data for initialization, and setting a starting mode; in the mode, a strategy of combining soft start with PI control is adopted, the duty ratio is calculated through a reference voltage slope and a PI regulator, and a PWM module generates four paths of driving signals to control the on and off of a full-bridge MOS tube; in the control process, analyzing system working conditions according to collected circuit data, and switching to a steady-state mode when a load throwing working condition occurs; in the mode, a composite duty ratio control law is constructed by using an LADRC linear active disturbance rejection control strategy, a complementary PWM signal is generated after amplitude limiting processing, and the system is driven to recover energy. Through mode switching and LADRC linear active disturbance rejection control, voltage oscillation under load throwing disturbance is effectively suppressed, and the dynamic stability and the voltage stabilization precision of the system are improved.

This invention discloses a driving method and driving device for a two-degree-of-freedom permanent magnet synchronous motor. d‑q The current command value of the shaft is used by the first coordinate transformation module to obtain the command value of the three-phase stator current; then it is compared with the actual value of the three-phase current fed back by sampling, and the feedback term of the three-phase command voltage is obtained through the PI regulator module; derivation d‑q The recursive formula for the change of shaft current with the control cycle is obtained by transforming the three-phase voltage fed back from the motor through the third coordinate transformation module. d‑q The axis voltage is obtained by transforming the feedback three-phase current through the second coordinate transformation module. d‑q shaft current and d‑q The shaft current command value is substituted into the recursive formula to obtain the three-phase command voltage feedforward term. The feedforward term is added to the feedback term to obtain the three-phase voltage command value, which is then input into the switching function module. The power devices in the controlled three-level inverter bridge module are determined according to the positive and negative values ​​of each command value. The required PWM wave is obtained by comparing it with the carrier wave, and finally the AC power is output to the three-phase permanent magnet synchronous motor.

This invention belongs to the field of power electronics technology, specifically relating to an automatic IGBT voltage drop compensation method for a three-phase inverter. First, the upper and lower arms of one phase of the three-phase inverter are turned off, the upper arm of another phase is turned off and the lower arm is turned on, while the upper and lower arms of the third phase remain operational. This constructs the three-phase inverter as a DC-DC converter topology. A microcontroller segments the current and rate of the PI regulator, changing the carrier frequency of the PWM module's voltage. The voltage drop of the IGBTs under different given currents and carrier frequencies is calculated using voltage equations. This enables automatic identification and compensation of the IGBT voltage drop in the three-phase inverter, as well as closed-loop control of the inverter's output current. This automatic voltage drop compensation method effectively solves the problem of inaccurate compensation for IGBT voltage drops caused by load current variations, thereby improving inverter output current distortion and significantly enhancing inverter performance.

This invention provides a DC-DC control method for new energy locomotives, comprising: acquiring the input current signals of each DC-DC converter unit, the SOC value of each power battery, and the output bus voltage acquisition value; constructing a dual closed-loop control structure of voltage outer loop and current inner loop; wherein, the voltage outer loop takes the deviation between the preset target value of the bus voltage and the acquisition value as input, and generates a total current command through an active disturbance rejection controller (ADRC); determines the target value of each current inner loop based on each SOC value and the total current command, so that the SOC of each battery tends to be consistent; the current inner loop takes the deviation between the target value of the current inner loop and the corresponding input current acquisition value as input, and generates a modulation wave signal through a PI regulator; performs amplitude limiting processing on the modulation wave signal; compares the amplitude-limited modulation wave signal with a triangular carrier wave to generate a drive pulse, and controls the operation of the power switch.

This invention discloses a fault-tolerant control method for a two-phase four-switch permanent magnet synchronous motor based on MPC. After an inverter switch failure, this method connects the motor neutral point to the DC power supply midpoint and reconfigures the inverter into a two-phase four-switch fault-tolerant operating topology using the remaining switches. The control system adopts a dual-loop structure. The outer loop controls the motor speed through a PI regulator and provides torque and flux linkage reference values ​​to the inner loop based on the maximum torque-to-current ratio. The inner loop employs model predictive direct torque control, using the stator voltage equation and stator current prediction model to obtain predicted flux linkage and torque values. The optimal switching state of the inverter is obtained using a value function, and the remaining switches are controlled to achieve fault-tolerant operation of the motor after a switch failure. This invention enables stable system operation even after a switch failure without requiring control strategy switching, effectively improving the safety and reliability of permanent magnet synchronous motor operation.

The invention discloses a synchronous phase modifier and STATCOM multi-target coordination optimization control method in an HVDC system. The method comprises the following steps: establishing a synchronous phase modifier reactive power regulation system based on SNA-PID; the deviation of the alternating current bus voltage of the inverter station is used as an input quantity, and the ITAE, the maximum absolute error value and the minimum steady-state deviation absolute value of the alternating current bus voltage of the inverter station are used as optimization targets of multi-target coordinated optimization control; and an NSGA-II multi-target optimization algorithm is adopted to carry out multi-target coordinated optimization on synchronous phase modifier reactive power regulation optimization parameters based on SNA-PID and voltage and current PI regulator control parameters of the STATCOM, so that multi-target coordinated optimization control of the synchronous phase modifier and the STATCOM in the HVDC system is realized. According to the invention, the inverter station AC bus voltage drop caused by system faults and load access can be effectively reduced, the inverter station AC bus overvoltage caused by fault elimination and load disconnection can be effectively suppressed, the recovery time of the system bus voltage is reduced, the probability of commutation failure of the system is effectively reduced, and the reliability of the system is improved. And the system stability is improved.