132 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 an improved droop control method for a sodium-ion battery parallel system in a micro-grid, and the method comprises the following steps: 1, calculating the actual droop control coefficient of a sodium-ion battery based on the charge state, health state and initial droop control coefficient of the sodium-ion battery, and further calculating the voltage reference of the sodium-ion battery; step 2, obtaining a direct current bus side voltage, and constructing a voltage compensator as a secondary compensation link of a sodium ion battery voltage reference by using a PI regulator, thereby ensuring that the direct current bus side voltage is stabilized at a voltage compensation reference value, and obtaining an actual droop control coefficient meeting the stability and the voltage reference of the sodium ion battery; and step 3, obtaining the actual output voltage and the actual inductive current of the sodium ion battery, and calculating the duty ratio of the bidirectional DC / DC converter by combining the adjusted voltage reference of the sodium ion battery obtained in the step 2. According to the method disclosed by the invention, each sodium-ion battery can be in an optimal working state.

The invention discloses a PMSM (permanent magnet synchronous motor) AC servo system speed control method based on improved particle swarm optimization optimization RBF (radial basis function) fuzzy neural network PID control, the system is composed of a speed outer ring and a current inner ring, and the current ring adopts a PI regulator. A speed loop is designed to be an RBF fuzzy neural network PID speed controller, an RBF fuzzy neural network is optimized by improving a particle swarm optimization algorithm, and optimal parameters kp, ki and kd suitable for the PID controller are output. Simulation analysis and experiment results show that compared with a common PID control strategy, a BP algorithm optimization fuzzy neural network PID control strategy and a particle swarm algorithm optimization RBF fuzzy neural network PID control strategy, the particle swarm algorithm optimization RBF fuzzy neural network PID control strategy based on the improved particle swarm algorithm has optimal control performance; the method has the advantages of being high in dynamic response speed, good in control stability, resistant to load disturbance and high in robustness, and the excellent speed control effect of the PMSM alternating current servo system can be achieved.

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 relates to an extended state type permanent magnet synchronous motor rotor position and speed estimation method. The invention relates to the technical field of motor control, and provides an extended state type counter electromotive force observer which takes alpha-beta axis current and alpha-beta axis total disturbance of a permanent magnet synchronous motor as system variables, alpha-beta axis actual current and action voltage as given values, and total disturbance of a system as observer output. And the back electromotive force of the permanent magnet synchronous motor is a main component for observing disturbance. The expansion state type phase-locked loop cancels a traditional PI regulator, the observed alpha-beta back electromotive force serves as phase-locked loop input, an observation angle error is obtained through calculation, and then the angle and speed of the motor are obtained and serve as output. In the angle compensation link, the phase difference between the observed counter electromotive force and the actual counter electromotive force is calculated according to the observer bandwidth and the motor rotating speed, a compensation angle is obtained through calculation, and accurate observation within the full-speed range is achieved.

The invention discloses a two-degree-of-freedom permanent magnet synchronous motor driving method and a driving device thereof. A current instruction value of a d-q axis passes through a first coordinate conversion module to obtain an instruction value of a three-phase stator current; then comparing with a three-phase current actual value fed back by sampling, and obtaining a feedback item of a three-phase instruction voltage through a PI regulator module; deriving a recursive relational expression of d-q axis current along with the change of the control period, processing three-phase voltage fed back by the motor through a third coordinate transformation module to obtain d-q axis voltage, substituting the feedback three-phase current through a second coordinate transformation module to obtain d-q axis current and a d-q axis current instruction value into the recursive relational expression, and finally obtaining a three-phase instruction voltage feed-forward item; and adding the feed-forward item and the feedback item to obtain a three-phase voltage instruction value, inputting the three-phase voltage instruction value into a switch function module, determining a power device in the controlled three-level inverter bridge module according to the positive and negative of each instruction value, comparing the power device with a carrier wave to obtain a required PWM wave, and finally obtaining an alternating current and outputting the alternating current to the three-phase permanent magnet synchronous motor.

The invention relates to the field of permanent magnet synchronous motor control, in particular to an RANF adaptive harmonic suppression method based on dustpan line optimization, which comprises the following steps: S1, establishing a d-q axis control model for a permanent magnet synchronous motor, listing voltage, current and electromagnetic torque equations, giving a harmonic current equation, and adopting an ANF adaptive notch extraction algorithm to obtain a harmonic current control model for the permanent magnet synchronous motor; obtaining estimated values of specific-order harmonic amplitude and phase, and generating harmonic compensation quantity from the estimated values by adopting a PI regulator so as to realize a steady-state indifference-free harmonic suppression effect; and S2, in order to solve the problem that the ANF adaptive harmonic suppression algorithm is difficult to follow the d-q axis current rapidly changing along with the direct current amount, an RANF adaptive harmonic suppression algorithm adopting an R regulator is proposed, the ANF following performance is greatly accelerated, and the practicability of the ANF is improved. When the motor load or the rotating speed changes, quick response can be achieved, system instability is avoided, the dynamic stability of the system is remarkably improved, and the application scene of ANF adaptive harmonic suppression in the permanent magnet synchronous motor is widened.

The invention provides a control method and a driving system of a high-speed magnetic suspension fan. The control method comprises the following steps: starting a magnetic suspension bearing active controller; acquiring three-phase current, rotating speed and rotor position signals of the high-speed magnetic suspension fan; determining a target phase current when two phases of the permanent magnet motor are conducted according to the three-phase current and the rotor position signal; the direct-current side voltage is converted into a rotating speed given value according to the direct-current side voltage-power curve relation, the difference value between the rotating speed given value and the rotating speed of the high-speed magnetic suspension draught fan is a first error value, and a current given value is output after the first error value passes through a first PI regulator; a difference value between the target phase current and the current given value is a second error value, the second error value passes through a second PI regulator, a duty ratio is output, the duty ratio is compared with the triangular carrier wave, and a PWM pulse signal is generated according to a comparison result; the PWM pulse signal controls on and off of a power switch device of the machine side medium voltage power converter; therefore, acceleration and deceleration operation of the high-speed magnetic suspension fan is controlled.

The invention relates to a quick charge boost control method and device for a vehicle, the vehicle and a storage medium. Comprising the steps of obtaining a system state and a power battery charging power demand of a current vehicle when the current vehicle has a quick charge boosting demand, and generating an initial charging current instruction according to the system state and the power battery charging power demand; obtaining a final charging current instruction based on a preset first PI regulator according to the initial charging current instruction, obtaining a three-phase winding neutral point output current instruction based on a preset second PI regulator according to the final charging current instruction, and obtaining a three-phase winding neutral point output current instruction based on a preset third PI regulator. And obtaining a duty ratio control instruction of a three-phase bridge arm according to the three-phase winding neutral point output current instruction, and performing interleaving control on a three-phase upper bridge arm of the motor controller power module according to the duty ratio control instruction of the three-phase bridge arm. Therefore, the problems that the unexpected torque is easy to realize and the charging efficiency is relatively low in the prior art are solved, and the charging efficiency is improved while the safety 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 a dual three-phase permanent magnet synchronous motor turn-to-turn short circuit fault adaptive diagnosis method, and belongs to the technical field of motor fault diagnosis. A mathematical model and an adjustable model of a dual three-phase motor turn-to-turn short circuit fault are established, space vector decoupling transformation of a multi-phase motor is combined, a short circuit fault component is introduced into a harmonic sub-plane of a stator voltage equation, and a fault characteristic value is designed by using an x-y current residual error of a real motor and the adjustable model. A fundamental wave amplitude is extracted through orthogonal Fourier transform to serve as a fault degree feature, a model reference adaptive law of an observer and a segmented PI regulator based on a mapping relation between a short-circuit current residual error and a fault turn ratio is constructed, PI parameters are dynamically adjusted according to the rotating speed and the load working condition, and adaptive feedback estimation of the short-circuit turn ratio is achieved. The fault feature extraction precision and real-time performance are improved, the fault-tolerant algorithm is simplified, the parameter design of the disturbance observer is optimized, the problem of diagnosis distortion caused by working condition changes is solved, and a motor monitoring optimization solution is provided.

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 relates to the technical field of motor control, and particularly discloses a permanent magnet synchronous motor stability control method, which comprises the following steps of: adjusting parameters of a PI regulator 1 and a PI regulator 2 to enable feedback dq axis current of a motor to follow given; a harmonic extraction module is operated, current harmonics of all times are obtained, harmonic currents id.xth and iq.xth are obtained through calculation, and x is an odd number which is not three times; calculating to obtain an effective value is.xth of each current harmonic wave; when is.xth is larger than the judgment threshold value delta I, the enabling coefficient Mx is equal to 1; when is.xth is smaller than or equal to the judgment threshold value delta I, the enabling coefficient Mx is equal to 0; adding a harmonic processing module, and operating the permanent magnet synchronous motor; operating a harmonic extraction module, and adjusting a gain coefficient Kx according to the distribution condition of each current harmonic; according to the invention, the current harmonics of each time of the motor are effectively combed, the current harmonics of the motor are reduced in a targeted manner, the torque ripple is reduced, and the stability of motor control is improved.

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 invention discloses a water system sodium ion battery double-closed-loop charging and discharging control method considering abnormal working conditions, which is realized through a voltage controller constructed by a PI regulator, a current controller constructed by a PI regulator and an abnormal working condition controller. Double-closed-loop control of the charging process and the discharging process is achieved through the voltage controller and the current controller, and abnormal working condition control is achieved through the abnormal working condition controller. According to the invention, a reasonable and effective charging and discharging control strategy is provided for the water-based sodium-ion battery system, and single control of the energy storage module composed of the water-based sodium-ion battery and the bidirectional DC / DC converter is realized.

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 present invention discloses a strong network stable voltage control method applicable to low line impedance, including: the voltage on the filter capacitor is sampled and subjected to a coordinate transformation of 3s / 2r to obtain a d-axis voltage quantity and a q-axis voltage quantity respectively. After comparing and taking the difference with the dq-axis voltage given reference value, a dq-axis voltage deviation signal is obtained, and then this deviation signal is input into the strong network stable voltage control as the input reference value of the current inner loop; the output result quantity of the dq-axis voltage loop is used as the input reference value of the current inner loop. At the same time, the current on the filter inductor close to the inverter side is sampled, and the difference between the two is sent to the PI regulator. The output of the current inner loop PI regulator serves as the modulation wave of the PWM modulation. After comparing with the triangular carrier wave, six-way PWM drive signals are generated to drive the on-off of the bridge arm switching tubes of the three-phase full-bridge inverter. This method has good compatibility and broadens the application range of the network-forming converter.

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 invention discloses a sensorless control method and system for an electrically excited synchronous motor, and relates to the technical field of motor control, and the technical scheme is characterized in that the air gap flux linkage of the electrically excited synchronous motor is observed through a closed-loop air gap flux linkage observer, and the closed-loop air gap flux linkage observer is composed of a voltage model and a current model; the voltage model and the current model are connected through a PI regulator; extracting rotating speed and position information in the air gap flux linkage through an orthogonal phase-locked loop model; detecting the voltage of the power grid by using a three-phase phase-locked loop; and selecting a corresponding control strategy according to the voltage drop depth of the power grid voltage so as to realize sensorless control of the electrically excited synchronous motor. The closed-loop air gap flux linkage observer is composed of a voltage model and a current model, the voltage model and the current model are connected through a PI regulator, the influence of direct current bias in a sampling signal on a flux linkage observation result can be restrained, and the performance of the models at a low speed is improved.

The present invention provides an adaptive control method based on a constant power load active compensation device, which is applicable to the technical field of isolated DC microgrid compensation devices, and comprises the following steps: a control system collects a constant power load input voltage u cpl and input current i cpl ; Determine whether the control system is in a steady state. If the control system is stable, proceed to the subsequent steps to adjust the control parameter R e Make corrections; determine whether the SOC of the battery at the input side of the compensation device is within the allowable range. If it is within the allowable range, then adjust the equivalent load resistance value R e Otherwise, the equivalent load resistance value R e The present invention can effectively improve the stability margin of the system, and at the same time adjust the compensation current by adjusting the slope of the equivalent resistance characteristic curve, thereby avoiding the high loss and low reliability problems under the traditional control strategy.

The present invention discloses a model predictive control strategy for a star-bridge-arm inter-phase coupled MMC applicable to low-frequency working conditions, including the following steps: Step 1: Establish discrete predictive models for each sub-arm and the star bridge arm on the main bridge arm, obtain the reference values and sampled values of the control quantities, and thereby predict the optimal arm voltages of the sub-arm and the star bridge arm; Step 2: According to the power balance condition, calculate the reference values of the DC component and the high-frequency circulating current component of the arm current to achieve the balanced control of the capacitor voltage of the phase unit and the capacitor voltage of the arm unit; Step 3: Combine the modulation strategy and the capacitor voltage balance control to determine the switching states of each sub-module. The present invention realizes the control of the capacitor voltage of the sub-arm, the capacitor voltage of the star bridge arm, the AC current, and the output common-mode voltage of the star-bridge-arm inter-phase coupled MMC applicable to low-frequency working conditions, greatly reduces the number of PI regulators in the control loop, simplifies the control structure, and improves the dynamic response ability of the system.

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.