100 results about "Repetitive control" patented technology

The invention relates to the technical field of power systems, in particular to a UPQC harmonic compensation method and system based on repetitive control, and the method comprises the steps: obtaining a load current signal and a voltage signal of a power distribution network, and extracting a harmonic instruction current based on the load current signal; and inputting the harmonic instruction current into a feed-forward channel constructed based on an adaptive filter, and generating a feed-forward control quantity. The phase and frequency of the voltage signal of the power distribution network are tracked in real time through a digital phase-locked loop, the fundamental frequency of the power grid is accurately solved, and the power distribution network can be accurately controlled. The internal model period and the phase lead compensation amount of the frequency adaptive repetitive controller are dynamically calculated, and the internal model structure of the repetitive controller is always matched with the current power grid frequency by updating the two core parameters in real time, so that the compensation precision decline caused by frequency deviation is avoided; and high-precision suppression of the periodic harmonic waves can be realized in a normal fluctuation range of the fundamental wave frequency of the power grid.

The invention belongs to the technical field of power electronics of power supply or power distribution, and provides a control method of a three-phase four-wire inverter, a controller and an inversion control system. A first control component is generated by using a phase angle, an inversion side three-phase current sampling value and a proportional integral compensator; a second control component and a third control component are generated by using a power grid voltage angular frequency, a neutral line current sampling value, a repetitive controller and a proportional resonance controller, the three control components are combined to control an inverter power switch tube, a proportional integral compensator is still adopted, the algorithm is simple, parameters are easy to design, and the reliability is high. And meanwhile, a repetitive-proportional resonance (RC-PR) composite controller is utilized to realize suppression of neutral line fundamental wave and harmonic current, and the method has faster dynamic response to load abrupt change, so that optimization of dynamic performance and steady-state performance is realized.

The invention discloses an anti-rollover control method and system for a balanced heavy forklift truck, and relates to the field of forklift truck intelligent control, and the method comprises the steps: collecting forklift truck working condition data through a sensor group, transmitting the data to a central controller through a CAN bus, and carrying out the preprocessing; inputting a rollover risk assessment algorithm, calculating a boundary condition of a static stability triangle and dynamic lateral moment balance, generating a rollover risk coefficient in combination with working condition data of the forklift, and outputting a decision instruction set; dynamic load adjustment is carried out through a hydraulic servo controller, and load pose parameters are obtained; a motor controller is driven to implement torque vector distribution, a braking energy recovery unit is involved, controllable slow-release braking is applied to wheels on the inner side, and adjusted wheel motion state parameters are obtained; and comparing the theoretical prediction model to carry out residual analysis, triggering a residual correction strategy, and carrying out repetitive control. The working state of the forklift is collected in real time and dynamically analyzed, so that the safety of the forklift in the operation process is improved.

The invention relates to a multi-mode control method and device for an energy storage converter. The method comprises the following steps: aiming at the operation of an energy storage converter in a network following mode, establishing a second-order infinite impulse response IIR filter, and establishing a low-voltage ride-through control strategy based on conforming to repetitive control; for the operation of the energy storage converter in an off-grid mode, a three-phase four-bridge-arm topology is adopted to provide a zero-sequence path, and a preset proportional multi-resonance control strategy is established; establishing a parallel pre-synchronization control strategy aiming at the operation of the energy storage converter in a network construction mode; and realizing multi-mode control of the energy storage converter based on a low-voltage ride-through control strategy conforming to repetitive control, a preset proportional multi-resonance control strategy and a parallel pre-synchronization control strategy. Any resonant frequency and filtering radius can be set to suppress the harmonic peak, the system stability is ensured, meanwhile, compared with a traditional pre-synchronization method, pre-synchronization can be completed without additional control links by only utilizing the self frequency modulation characteristic, and control resources are greatly saved.

The invention relates to the technical field of power electronics, in particular to a predictive compensation quasi-sliding mode control method for a three-phase four-leg three-level inverter, and the method comprises the steps: building a continuous state space model; discretizing the continuous state space model, constructing a discrete state space model, defining an output error of the output voltage and a derivative of the output error, and defining a sliding mode function based on the output error of the output voltage and the derivative of the output error under the theory of introducing quasi sliding mode control; constructing a prediction model and predicting a sliding mode function value at a next moment, introducing an expansion model to extract a model error, and correcting a defined sliding mode function based on a deviation between a prediction value and the model error; constructing a repetitive controller to extract a periodic error component and generate a compensation signal; and fusing the compensation signal with an equivalent control quantity constructed based on the expansion model to form a final control input for the driving system. According to the method, buffeting can be suppressed to a great extent, the steady-state performance can be optimized, and fast dynamic response is taken into account while the robustness of the system is guaranteed.

The invention discloses a suspension flux linkage repetitive control method for a single-winding bearingless flux switching motor. A rotor dynamic eccentric suspension flux linkage model is established according to a magnetic suspension rotor system of the single-winding bearingless flux switching motor; a model compensation repetitive controller with an integral element, a model compensator and a same-frequency phase shift notch filter is arranged in the magnetic suspension rotor system; the integration element is used for eliminating steady-state errors, the model compensator is used for obtaining inverse system output signals so as to obtain accurate displacement control signals, and the notch filter is used for reducing same-frequency pulsation of rotor radial displacement; an expected suspension flux linkage is obtained through calculation of the model compensation repetitive controller, the expected suspension flux linkage is compared with an actual flux linkage obtained by the flux linkage observer to obtain a flux linkage error, expected voltage is obtained through calculation of the flux linkage error, and therefore an inverter switching signal is obtained. According to the method, the radial displacement pulsation of the rotor under the steady-state working condition and the displacement sudden change phenomenon under the dynamic working condition are effectively treated, and good control is achieved.

The invention discloses a permanent magnet synchronous motor robust complex coefficient repetitive control method based on a position domain internal model, and relates to the technical field of permanent magnet synchronous motor control, and the method comprises the steps: constructing a time domain improved complex coefficient repetitive controller through employing the time domain periodic characteristics of a main shaft rotating speed; secondly, on the basis of the position domain periodic characteristics of the cutting force, a position domain repetitive expansion state observer is constructed, and on-line estimation is carried out on aperiodic disturbance such as parameter perturbation and position domain periodic disturbance caused by the cutting force; and finally, deducing a system stability condition by applying a separation design principle and a small gain theorem, and synchronously optimizing controller parameters by adopting an optimization algorithm. The invention discloses a system design method based on time domain complex coefficient repetitive control and a position domain repetitive expansion state observer. An improved complex coefficient repetitive control system based on a position domain repetitive expansion state observer is designed to realize feed-forward compensation of periodic disturbance and non-periodic disturbance of a position domain and fast and high-precision tracking of a time domain periodic reference rotating speed signal.

The invention discloses an anti-frequency interference V2G converter low harmonic combination control method, the V2G converter is a voltage type PWM rectifier, and the method is characterized in that a voltage outer loop controller in the control method adopts a proportional integral controller, a moving average filter is directly connected in series to the output of the voltage outer loop controller; interference of periodic signals in the direct current bus voltage on the current reference signals is suppressed, so that the amplitude of the current reference signals is pure direct current quantity; in the current loop controller, a repetitive controller is used as a feedforward controller and is combined with a weighted average deadbeat controller, an insertion type composite controller is constructed, coefficients are rapidly updated by adopting a Lagrange interpolation method, and a delay value is continuously controlled, so that the repetitive controller and a moving average filter have frequency self-adaptive characteristics; the problem of performance degradation of a traditional fixed frequency controller during frequency fluctuation is solved, and the anti-frequency interference characteristic of the converter is enhanced.

The present invention provides a method for flexible harmonic control of a ship photovoltaic inverter. The method adopts a control structure in which a grid-connected current command current link and a compensation command current link are connected in parallel, so as to realize flexible switching between a harmonic compensation mode and a harmonic suppression mode. The voltage and current dual closed-loop control is adopted. The voltage outer loop adopts PI control to stabilize the DC side capacitor voltage and output the grid-connected active command current. The current inner loop adopts a parallel PI+repetitive controller to realize zero-static error tracking of the command current. In the harmonic compensation mode, the inverter output current includes the grid-connected active current and the compensation current to compensate for the harmonic current generated by the nonlinear load of the power grid. In the harmonic suppression mode, the inverter's ability to suppress power frequency harmonics is effectively improved, high-quality grid-connected current is output, and the total harmonic distortion rate of the grid-connected current is reduced. The present invention realizes the use of the redundant capacity of the inverter to compensate for grid harmonics when the inverter is lightly loaded; when the inverter is heavily loaded or fully loaded, the inverter operation stability is improved.

The invention discloses an active power filter control method and system suitable for frequency fluctuation, and the method employs an FIR filter based on a Lagrange interpolation method to correct the decimal part of the sampling times, and employs a variable bandwidth adjustment internal model control (VBAI) technology to improve the bandwidth after frequency fluctuation. The problem that the control effect is seriously reduced due to the fact that traditional repeated control sampling times change caused by power grid frequency fluctuation is effectively solved, and control gain stability under frequency fluctuation is guaranteed.

An MMC direct current port impedance modeling method adopting an embedded repetitive controller relates to the technical field of harmonic suppression and impedance modeling of a flexible direct current power transmission system, and comprises the following steps: 1) constructing an MMC main circuit equivalent circuit; 2) converting the MMC equivalent circuit to a frequency domain; 3) calculating steady-state harmonic waves; 4) constructing a main circuit frequency domain linearization model; 5) constructing a control circuit frequency domain model; and 6) determining an MMC direct current port impedance model adopting the embedded repetitive controller. Based on multi-harmonic linearization, a complete double-closed-loop control structure is considered, accurate modeling is performed on the MMC system adopting the embedded repetitive controller, the accuracy of stability analysis is ensured, operation is convenient, and expansibility is high.

The invention discloses a repetitive control method and device for an active power filtering device, and the method comprises the steps: carrying out the adjustment of the harmonic frequency of a controller according to a harmonic signal obtained from a main circuit of the active power filtering device, calculating the harmonic signal through a harmonic detection module of the adjusted controller, obtaining a fixed delay parameter, and carrying out the calculation of the fixed delay parameter. And calculating according to the fixed delay parameter and the voltage frequency output by the power grid phase-locked loop to obtain a delay parameter so as to judge whether the harmonic signal needs to be compensated or not, if so, calculating a corresponding compensation parameter according to the delay parameter, and outputting a corresponding compensation current according to the compensation parameter to compensate the harmonic signal. Corresponding parameters of the controller are adjusted according to the harmonic frequency of the harmonic signal, adaptive adjustment of different harmonic scenes is achieved, and adaptability and universality to the different harmonic scenes are improved; through the repetitive control method, repetitive tracking control is carried out on the harmonic signals, and signal delay, storage resource waste and repetitive control operation complexity are reduced.

The invention discloses a repetitive control-based circulating current suppression method between grid-forming type energy storage units, and relates to the technical field of power electronics and control, the method adopts three rings of power, voltage and current to regulate and control a grid-forming type multi-machine parallel inverter, a repetitive controller is introduced into a current inner ring, and the repetitive controller is introduced into a current outer ring to control the circulating current between the grid-forming type energy storage units. The method has the advantages that periodic harmonic current is accurately tracked and suppressed, meanwhile, a narrow-band resonance circuit and LC filter state feedback and pole assignment design are introduced into a current loop, LC filter resonance peaks are effectively eliminated through LC filter state feedback and pole assignment, typical harmonic circulation in a parallel system is further suppressed through the narrow-band resonance circuit, and the harmonic current suppression efficiency is improved. Efficient suppression of circulation among the units and uniform distribution of power are further realized; according to the technical scheme, the stable operation of the system can be guaranteed, the power sharing capability and the grid-connected adaptability of the energy storage unit are improved, a complex distributed communication structure is avoided, and the operation reliability of the network construction type energy storage system in a complex power grid environment is improved.

The invention relates to a plug-in type second-order feed-forward dual-mode repetitive control method. The method comprises the following steps: establishing a single-phase LCL type grid-connected inversion model based on a PP-SFDMRC controller; according to the single-phase LCL type grid-connected inversion model, a transfer function of a controlled object is obtained, a PP-SFDMRC controller structure is discretized, and a discrete transfer function of an internal model of the SFDMRC is obtained; the method comprises the following steps: acquiring an error transfer function of a PP-SFDMRC controller based on an SFDMRC internal model discrete transfer function by taking SFDMRC internal model stability as a target, converting the error transfer function into a characteristic polynomial, and determining a stability condition of the PP-SFDMRC controller; through stable conditions, corresponding parameters of the PP-SFDMRC controller are set, and odd and even harmonics are controlled to different degrees. The PP-SFDMRC strategy provided by the invention has excellent dynamic performance and super-strong adaptability to power grid frequency change.

The invention discloses a hybrid active power filter system harmonic suppression method and system, and the method comprises the steps: taking the size of load harmonic and the impedance of a power grid as the input of a particle swarm optimization method, and obtaining the optimal value of a passive power filter capacitor and the optimal value of an inductor; extracting a load harmonic current ILoadh after the capacitance and inductance of the passive power filter are optimized, taking the load harmonic current ILoadh as the input of a repetitive controller and an additional damping controller, and superposing the output of the repetitive controller and the output of the additional damping controller to obtain a final harmonic compensation reference current Icxref of the active power filter; and taking the harmonic compensation reference current Icxref of the active power filter as the input of a proportional resonance controller, performing PWM (Pulse Width Modulation) on the output of the proportional resonance controller, generating a driving signal, and controlling the on-off of a switching tube of the active power filter. Harmonic amplification can be effectively eliminated, fundamental frequency resonance is suppressed, and the overall performance is improved.

The invention provides an off-line and on-line collaborative optimization MMC harmonic elimination method for harmonic constraint driving, and relates to the technical field of power electronics, S1, generating a switching angle training set and a parameter fluctuation label through clustering analysis and a differential evolution algorithm according to power grid parameters and MMC operation parameters; and S2, extracting harmonic characteristics by using a harmonic detection technology, predicting a switching angle through a neural network, and outputting a final switching angle in combination with a repetitive control link to realize harmonic suppression. According to the off-line and on-line collaborative optimization MMC harmonic elimination method based on harmonic constraint driving, an MMC under a low level number can always keep a low harmonic content level under the complex conditions of different modulation ratios and access to a new energy field station.

The invention relates to a dual three-phase permanent magnet synchronous motor model-free prediction repetitive control method and system based on a double-subspace virtual vector, and the method comprises the steps: decomposing the vector of a motor into a fundamental wave subspace and a harmonic wave subspace which are orthogonal to each other based on an obtained operation parameter, and constructing an independent super-local model in the two subspaces; constructing a linear expansion state observer in the fundamental wave subspace, and constructing a repetitive expansion state observer based on repetitive control in the harmonic wave subspace; respectively synthesizing an independent virtual voltage vector set and a decoupling virtual voltage vector set in the two subspaces; and calculating reference voltage vectors of the two subspaces, selecting an optimal virtual voltage vector and an optimal decoupling virtual voltage vector, respectively calculating optimal duty ratios, synthesizing control signals applied to each bridge arm of the inverter, and driving the dual three-phase permanent magnet synchronous motor. According to the method, model-free control of double sub-spaces is realized, model parameters of a motor system of an algorithm are controlled, and better robustness is shown when the parameters are mismatched.

This application provides a control method, system, and electronic device for a PWM rectifier. The control method includes: determining the actual current of the PWM rectifier and determining a current error based on the actual current and a reference current; obtaining a first control parameter based on the current error using a preset algorithm; determining an error compensation value based on the current error using a repetitive controller, and compensating the first control parameter with the error compensation value to obtain a second control parameter; determining the fundamental frequency of the modulation wave based on the second control parameter, and obtaining a control signal based on the fundamental frequency of the modulation wave using a discontinuous pulse width modulation (DPWM) method to control the PWM rectifier. This application introduces a repetitive controller into the discontinuous pulse width modulation (DPWM) method, which improves the problem of large current harmonics caused by periodic errors due to periodic entry into clamping state in the DPWM modulation method, thereby improving control accuracy.

The present invention discloses a method for robust complex coefficient repetitive control of a permanent magnet synchronous motor based on a position domain internal model, which relates to the technical field of permanent magnet synchronous motor control. First, the time domain periodic characteristics of the spindle speed are used to construct an improved time domain complex coefficient repetitive controller. Second, based on the position domain periodic characteristics of the cutting force, a position domain repetitive extended state observer is constructed to online estimate non-periodic disturbances such as parameter perturbations and position domain periodic disturbances caused by the cutting force. Finally, the separation design principle and the small gain theorem are applied to derive the system stability conditions, and an optimization algorithm is used to synchronously optimize the controller parameters. The system design method based on time domain complex coefficient repetitive control and position domain repetitive extended state observer of the present invention designs an improved complex coefficient repetitive control system based on the position domain repetitive extended state observer to achieve feedforward compensation for position domain periodic disturbances and non-periodic disturbances and fast and high-precision tracking of time domain periodic reference speed signals.

The invention discloses an inverter special waveform control system which comprises a repetitive control module, and the repetitive control module comprises a repetitive control internal model, an advanced link zm, a gain parameter Kr and a forward low-pass filter S (z) which are connected in sequence. The repetitive control internal model comprises a backward low-pass filter Q (z), a backward delay link z-N and a forward delay link z-N. A high-frequency special waveform is controlled by applying a repetitive control method, and a control system can have very high gains on fundamental waves and infinite-dimensional harmonic waves by introducing an internal model of a periodic signal, so that tracking of the high-frequency special waveform is realized.

The invention relates to the technical field of power systems, in particular to an event-triggered proportional-integral repetitive controller and method and a related device. Two channels of the event triggering block are respectively provided with two adjusting coefficients, and tracking error signals are respectively input into a repetitive controller and a proportional-integral controller after being adjusted; when a triggering condition is met, two adjustment coefficients of a forward channel of the event triggering block change along with time; the tracking error is increased, the adjustment coefficient of the repetitive control channel is reduced, and the adjustment coefficient of the proportional-integral channel is increased; and after a trigger period, the two adjustment coefficients of the event trigger block are gradually recovered to default values along with the reduction of the tracking error signal. According to the invention, decoupling of the proportional-integral repetitive controller is realized, the dynamic performance is improved, and output distortion of multiple periods caused by mismatching of the dynamic performance of the proportional-integral controller and the repetitive controller is avoided.

The invention discloses a method for suppressing current fluctuation of a permanent magnet synchronous motor under a propeller load, and the method comprises the steps: firstly building an electromagnetic torque mathematical equation and a stator voltage and current equation of a PMSM under a dq-axis rotation coordinate according to a basic structure and a working principle of the permanent magnet synchronous motor; then, according to a blade element theory and aerodynamic characteristics of the propeller, establishing mathematical models of a'rotating speed-torque 'relation and a'rotating speed-tension' relation of the propeller; establishing a current loop mathematical model containing periodic and non-periodic disturbance; analyzing and constructing a current loop active-disturbance-rejection controller according to the current loop mathematical model containing disturbance, and analyzing the stability of the constructed current loop active-disturbance-rejection controller according to a Nyquist stability criterion; and finally, realizing high-precision control of a PMSM current loop by using a current loop active disturbance rejection controller method containing a repetitive controller, realizing accurate control of the current loop of the permanent magnet synchronous motor under a propeller load, and ensuring stable operation of the permanent magnet synchronous motor under a dynamic load and a complex working condition.

The invention provides a photovoltaic inverter harmonic suppression system and method, and the method comprises the steps: obtaining a target current error of a current period, enabling a repetitive control branch to generate a branch period delay of the current period according to the target current error, a gain coefficient corresponding to the target current error and a branch period delay of a previous period, and collecting the branch period delay as a total delay of the current period; and inputting the total delay of the current period into a PI controller, so that the PI controller generates a target voltage instruction. The tracking capability of the PI controller on the fundamental current is reserved, the current inner loop design of a common inverter is not affected, and the suppression effect on the periodic harmonic waves is enhanced through the repetitive controller. Meanwhile, by optimizing the design of the repetitive controller, the repetitive controller becomes a composite repetitive controller comprising at least two repetitive control branches, the effective bandwidth of the repetitive controller is widened, the repetitive controller can adapt to the fluctuation of the power grid frequency, and therefore the excellent grid-connected current harmonic suppression performance is kept within the wide frequency change range.

The application discloses a network-constructing energy storage converter control method based on a repetitive control inner loop, comprising the following steps: generating a power grid angular frequency reference value by integrating adjustment of an active power deviation; generating a power grid amplitude reference value by integrating adjustment of a reactive power deviation; generating an inner loop current reference instruction through a voltage loop controller according to a voltage loop voltage reference value, superposition of a power grid current feedforward branch and a voltage loop dq decoupling branch; generating a current loop voltage reference value through a current loop controller and a repetitive controller in parallel processing according to the inner loop current reference instruction, and superposition of a current loop dq decoupling branch; and generating a corresponding output current according to the current loop voltage reference value. By designing a lead compensation link and a compensator, the problem of difficult parameter setting and easy instability of a traditional repetitive controller is improved, and stable operation of the system is ensured.

The application discloses a control strategy based on combination of a pre-filter friction compensator and improved repetitive control, and specifically comprises the following steps: step 1, a pre-filter friction compensator is added to a P / PI cascade controller to improve the anti-friction interference capability of a driving system; step 2, a transfer function of an output voltage of the driving system and a tracking error is determined; step 3, specific parameters of a LuGre model in the pre-filter friction compensator are obtained; step 4, a repetitive controller is designed; step 5, an action time period of the repetitive controller determined in step 4 is set at motion commutation to obtain a segmented repetitive control; and step 6, the segmented repetitive control obtained in step 5 is combined with the designed pre-filter friction compensator to form an improved repetitive control framework. The method combines the pre-filter friction compensation control with the segmented repetitive control, greatly improves the error and convergence rate at the motion commutation of each cycle, and reduces the influence of the friction interference on the product processing quality.

The present invention provides a simulation method for a retaining ring structure in a chemical mechanical polishing process, comprising constructing a CFD model of the chemical mechanical polishing process, dividing a fluid region into discrete grids, wherein the grids are non-repetitive control volumes, and within each control volume, using a momentum equation, a continuity equation, and a VOF model to control the motion of the polishing liquid fluid, and a DPM model to control the motion of the abrasive, integrating the momentum equation, the continuity equation, and the VOF model for each control volume to obtain a discrete equation, solving the discrete equation to obtain simulation data, the simulation data including abrasive motion data, plotting the abrasive distribution and the abrasive aggregation state on the polishing pad and / or the wafer edge based on the abrasive motion data, and having the beneficial effects of visualizing the polishing liquid / abrasive flow through a finite element method, helping to understand the influence of the retaining ring on the polishing liquid flow, providing a retaining ring structure improvement to solve wafer edge over-polishing, conforming to actual production processes, and having high simulation accuracy.

This invention relates to a model-free predictive repetitive control method and system for a dual-subspace virtual vector dual-three-phase permanent magnet synchronous motor. Based on the acquired operating parameters, the motor's vectors are decomposed into mutually orthogonal fundamental and harmonic subspaces, and independent hyperlocal models are constructed in both subspaces. A linear extended state observer is constructed in the fundamental subspace, and a repetitive extended state observer based on repetitive control is constructed in the harmonic subspace. Independent virtual voltage vector sets and decoupled virtual voltage vector sets are synthesized in the two subspaces, respectively. Reference voltage vectors for the two subspaces are calculated, and the optimal virtual voltage vector and optimal decoupled virtual voltage vector are selected. The optimal duty cycle is calculated for each subspace, and control signals are synthesized and applied to each arm of the inverter to drive the dual-three-phase permanent magnet synchronous motor. This invention achieves model-free control in a dual-subspace manner, and the control algorithm for the motor system's model parameters exhibits better robustness in the event of parameter mismatch.

The invention discloses a nested odd repetition proportion controller and a design method thereof. The design method comprises the following steps: S1, determining a transfer function of a controlled object; s2, constructing a nested odd repetitive control internal model; the nested odd repetitive control internal mold comprises an external odd repetitive control internal mold and an internal odd repetitive control internal mold which are arranged in a nested manner; s3, compensating the nested odd repetition control internal model by adopting a system compensator and a phase lead compensator so as to construct a nested odd repetition controller; s4, aiming at the controlled object, adding a feedforward controller to the nested odd repetition controller to obtain a nested odd repetition proportional controller; and S5, designing and selecting nested odd repetition proportion control parameters to form a stable nested odd repetition proportion control system. According to the invention, high gain capability is realized at odd harmonics, repeated control of even harmonics can be suppressed, and harmonic suppression capability and strong robustness when power grid frequency fluctuates are improved.

The present disclosure relates to a kind of energy storage converter multi-mode control method and device.Wherein, the method includes: for energy storage converter in grid-connected mode, by creating second-order infinite impulse response IIR filter, establish low voltage ride through control strategy based on compliance repeat control;For energy storage converter in off-grid mode, three-phase four-bridge topology is used to provide zero sequence path, establish preset proportional resonant control strategy;For energy storage converter in grid-constructing mode, establish parallel pre-synchronization control strategy;Low voltage ride through control strategy based on compliance repeat control, preset proportional resonant control strategy, parallel pre-synchronization control strategy are used to realize multi-mode control to the energy storage converter.The present disclosure can set any resonant frequency and filter radius to suppress the resonant peak, ensure system stability, compared with traditional pre-synchronization method only using its frequency modulation characteristics, without additional control link can complete pre-synchronization, greatly save control resources.

The application discloses a torque ripple suppression method for a brushless doubly-fed motor, which comprises the following steps: firstly, a current loop and a rotating speed loop model of the brushless doubly-fed motor are established; then, an active disturbance rejection controller is established according to the current loop and the rotating speed loop model, wherein the active disturbance rejection controller comprises a d-axis improved current controller, a q-axis current loop active disturbance rejection controller and a rotating speed loop active disturbance rejection controller; the d-axis improved current controller comprises a d-axis current loop active disturbance rejection controller and an improved repetitive controller connected in parallel with the d-axis current loop active disturbance rejection controller; and then, the brushless doubly-fed motor is controlled by using the established active disturbance rejection controller. The active disturbance rejection controller is combined with the improved repetitive controller, the extended state observer is used for disturbance estimation, and the disturbance contains a coupling term, so that the current dynamic response is faster, and the parameter robustness is stronger; meanwhile, the improved repetitive controller connected in parallel can overcome the high-frequency current harmonics introduced by uncontrolled rectification, and can also limit the dynamic response to not produce excessive overshoot when the working condition is suddenly changed.