53 results about "Finite control set" patented technology

The invention discloses a finite control set model predictive control method for a multi-motor control system. The finite control set model predictive control method is applied to the multi-motor control system which is composed of m permanent magnet synchronous motors. The finite control set model predictive control method for the multi-motor control system comprises the steps that the electrical quantity of the multi-motor control system is acquired; virtual reference voltage vectors are predicted and a value function is optimized, wherein for each motor, the corresponding virtual reference voltage vector existing at the k moment is calculated, and the value function is established; the process of optimizing the value function is simplified according to the vector zoning method; the common mode voltage of the multi-motor control system is restrained by adding the common mode voltage constraint to the method. Compared with a traditional finite control set model predictive control (FSC-MPC) method, the FSC-MPC method for the multi-motor control system has the advantages that on the basis that the control effect of the traditional method is maintained, the method implementing time is effectively shortened; meanwhile, cooperative control over the speeds of the multiple permanent magnet synchronous motors is achieved, and the purpose of restraining the common mode voltage is achieved.

The invention discloses a permanent magnet synchronous motor torque control strategy based on a flux linkage vector. According to the strategy, on the basis of finite set model prediction control, through analyzing internal relations between an electromagnetic torque reference value, a stator flux linkage reference value and a flux linkage vector phase angle, the electromagnetic torque reference value and the stator flux linkage reference value are converted into a flux linkage vector reference value, and a value function based on a flux linkage vector error is constructed. According to the strategy, the value function is utilized to evaluate action effects of alternative voltage vectors of a control set, switch frequency reduction for loss reduction is realized, a finite control set mode is employed, an optimum duty ratio of each alternative voltage vector is acquired through calculation when the value function is made to be smallest, the optimum duty ratio is further utilized, and the torque control strategy based on the flux linkage vector is realized.

The invention discloses a simple-target three-level active power filter control method based on finite control set model prediction. The simple-target three-level active power filter control method based on finite control set model prediction is characterized by performing optimization and integration on the implementation method of three control targets: harmonic current compensation, direct current side voltage stabilization and direct current side midpoint potential balancing of a three-level active power filter; and realizing optimization control of the three control targets only by taking the output current as a constraint term in a constraint function. The simple-target three-level active power filter control method based on finite control set model prediction simplifies the constraint function, saves selection of the weighting factor in the constraint function, reduces the computational complexity brought by weighting factor setting and computation of multiple constraint terms, improves dynamic response of the system, and realizes balancing control of multiple targets.

The invention relates to a finite control set model predictive voltage control method containing delay compensation. NPC inverter load side voltage is controlled through finite control set model predictive control, and delay compensation is performed on a control algorithm at a new sampling moment by directly applying the switch state predicted in advance and then predicting the new switch state so that inverter output control can be realized. The finite control set model predictive voltage control method containing delay compensation has great control effect and better robustness and reliability.

The invention discloses a finite control set model predictive control method of an LCL type energy storage converter. The state variable estimation is combined with delay compensation. The converter side current, the capacitor voltage and the grid current are estimated by sampling grid current, and the error between the sampled grid current and the estimated grid current is subjected to a correction matrix to reduce the influence caused by model mismatch and parameter drift, and then the estimated state variables are subjected to the finite control set model predictive control algorithm with the delay compensation link so as to improve the system performance and finally realize the control of the LCL energy storage converter. The number of sensors can be reduced, the cost can be reduced and the reliability of the system can be enhanced; and the influence of calculation delay on the system performance is eliminated through combination of the delay compensation algorithm and thus the quality of incoming current is improved.

The invention relates to the technical field of speed control of a permanent-magnet synchronous motor, and particularly discloses a neural network-based direct speed control method of a permanent-magnet synchronous motor. The method comprises the steps of 1, detecting each state quantity of the motor at an arbitrary moment; 2, training a neural network so that a local dynamic model of the system is approached; 3, forecasting each state quantity of the system within a future period by the neutral network; 4, evaluating a forecast result of a limited control set by an index function, and selecting control quantity with optimal index; and 5, outputting an inverter control signal corresponding to the control quantity with the optimal index to an inverter, and completing control of a period. Bythe method, the influence of a current ring in a traditional cascade connection controller on bandwidth of a speed ring is prevented, and the dynamic response performance of the system is improved; and meanwhile, the method has good control accuracy and has favorable adaptability on external interference and parameter change, and the robustness of the system is greatly improved.

The invention discloses a five-phase inverter model prediction current control method based on duty ratio optimization. The method specifically comprises the steps of selecting four adjacent large vectors of an alpha-beta subspace to synthesize a virtual voltage vector according to a specific duty ratio, and eliminating the harmonic voltage of an x-y subspace; selecting the virtual voltage vectorto construct a finite control set, and simplifying a prediction model and an evaluation function; estimating the action time of the virtual voltage vector in each control period, optimizing the duty ratio, and reducing current ripples; selecting two large vectors in opposite directions to be combined according to the same duty ratio, the volt-second value of each control period is adjusted, and therefore common-mode voltage is restrained; and designing and optimizing a switch sequence, and realizing average switching action times of each bridge arm. According to the invention, the common-modevoltage is reduced by 80% while the low-order harmonic current is effectively suppressed; and the evaluation function is simplified, the current tracking precision is improved, and the current ripplesare reduced.

The invention discloses an improved model predictive torque control method for an NPC three-level converter-PMSM system. The method comprises: calculating an offset threshold value, dividing the midpoint voltage offset of the two direct-current support capacitors in the converter into two types of areas according to the offset threshold value: for the larger midpoint voltage offset, calculating the actual amplitude and phase of the medium and small vectors of the converter according to the current midpoint voltage offset in each sampling period, and carrying out sector dynamic division; constructing a value function and a finite control set according to the control targets of different regions, obtaining an optimal voltage vector, and outputting the optimal voltage vector; and adding deadtime to the control time corresponding to the optimal voltage vector, and outputting a PWM signal to the permanent magnet synchronous motor for control. According to the method, the torque and flux linkage control performance can be improved, the calculated amount is reduced, and the problems that in existing control, the weight coefficient setting process is complex, and the system torque, flux linkage and current control performance is reduced when the midpoint voltage deviation amplitude is large are solved.

The invention belongs to the technical field of control technology and metal forming, and particularly relates to a limited control set-based sensorless press machine full-closed-loop control system and method. According to the system and method, the difference between a forming process curve and the actual position of a sliding block is used as a whole machine control system control instruction position input, a kinetic model is established, torque calculation is carried out, and the calculated result is taken as an input of a torque prediction control algorithm. The system and method have the advantages that a non-sensing control algorithm module and a torque prediction algorithm module of a limited control set are arranged in a servo motor driver, the rotating speed and the electromagnetic torque prediction value are calculated, the value function is finally obtained, the position information of the sliding block can be added into the value function to control the position of the sliding block to not be overly controlled, the dynamic performance is obviously improved, the anti-interference performance of the motor servo driver can be improved, the reliability is remarkably improved, and the cost of a servo motor is greatly reduced.

The invention discloses a nonlinear predictive control method for acquiring the maximum wind energy of variable-speed wind turbine generator system. The method includes: introducing a dynamic area toconstrain the allowed range of generator torque; determining the finite control set of candidate generator torque; searching for optimal generator torque sequence; using the first element of the optimal generator torque sequence as the controller output. The method has the advantages that the optimal generator torque sequence is directly searched on the basis of a variable-speed wind turbine generator system nonlinear prediction model, so that the provided controller can sufficiently utilize a large prediction range; the method has high efficiency and excellent performance in maximum wind energy acquiring.

The invention provides a non-linear prediction pitch control method based on wind speed in-advance measuring. The method comprises the steps of firstly, introducing a dynamic area to restrain the preset allowable range of the given pitch angle change rate of a wind generating set; secondly, within the preset allowable range, determining the limited control set of the given pitch angle change rateof a candidate wind generating set; thirdly, through the limited control set, searching the given pitch angle change rate sequence of an optimal wind generating set; and fourthly, taking the first element of the given pitch angle change rate sequence of the optimal wind generating set as the controller output. The non-linear prediction pitch control method based on wind speed in-advance measuringhas the important effect on unit safety, stability and efficient running.

The invention relates to a microgrid island control method by mixing droop control and model predictive voltage control. The microgrid island control method by mixing the droop control and the model predictive voltage control comprises the steps that the droop control is combined with the finite control set model predictive voltage control and applied to the control over a microgrid inverter in the island state; and when an island appears in the operation process of a smart grid, the droop control technology is used for producing reference voltage output by the microgrid inverter, on the basisof reducing the complexity of a control system and design difficulty of the control system, finite control set model predictive voltage control technology is used for enabling the microgrid inverterto output the reference voltage required by the control system, and the voltage is supplies to local load. The microgrid island control method by mixing the droop control and the model predictive voltage control facilitates reducing the design difficulty and complexity of the microgrid inverter control system in the off-grid island state and reducing the inertia coefficient of the control system.

The invention discloses an NPC three-level rectifier optimization finite control set model prediction method, and relates to the field of power electronics and power transmission. According to the method, firstly, a three-level PWM rectifier discrete prediction model is established and initialized, state sampling is carried out on a PWM rectification system, then a predicted value and an expected value of a system state are calculated according to a recorded optimal switching vector, finally, whether a current error and a neutral-point potential error meet reference deviation at the same time or not is judged, and finally, whether the current error and the neutral-point potential error meet reference deviation or not is judged. If yes, recording the switching vector at the previous moment, and outputting the switching state; if not, the reference voltage is calculated, the sector where the reference voltage is located is judged, the value function of the switching state of the sector is solved, the switching vector with the minimum value function is recorded, and the switching state of the switching vector is output. The method has the advantages that when the current error and the neutral-point potential error are controlled within a certain range, the average switching frequency of the converter can be reduced, when the current error and the neutral-point potential error exceed the range, 27 times of traversal are reduced to 10 times, the calculation burden is reduced, and the method is suitable for being applied to a high-power PWM rectifier.

The present invention discloses a switching type control method based on double loop predictive control, which belongs to the field of power electronic converter technology and industrial control. The invention is based on double loop predictive control, and the deadbeat control is adopted by the outer loop control to improve the overall performance of the system (the system refers to the implementation object of the control method, and generally refers the power electronic converter); a switching type control method is adopted by the inner loop control: when the system is in the steady state, the deadbeat control is adopted to ensure the steady state accuracy of the system and to achieve the fixed switching frequency; when the system is in the transient state, it is switched to the finite control set model predictive control to ensure the rapid transition of the system to the steady state. The switching type control method based on double loop predictive control disclosed by the invention has the respective advantages of both kinds of predictive control, and the deadbeat control is adopted by the inner loop to greatly improve the overall performance of the system, which can well meet the working requirements of the power electronic system.

The invention provides a model prediction control method of an LCL type battery energy storage converter. The method achieves the estimation of a voltage of a power grid through the construction of an intermediate variable (flux linkage), and serves as a basis for improving a finite control set model predictive control algorithm. And then the estimated power grid voltage passes through a delay compensation link so that the influence of calculation delay on the system performance is eliminated, and the quality of a network access current is improved. Phase locking is carried out by adopting the flux linkage so that the power grid voltage phase information is estimated, and the same phase of the network access current and the power grid voltage is realized. By adopting the method of combining power grid voltage estimation, flux linkage-based phase locking and delay compensation, control without a power grid voltage sensor can be realized, and the quality of the network access current can be improved and network access of a power grid current unit power factor can be realized while the number of sensors is reduced and the cost is decreased.

The invention discloses an energy storage converter improved finite control set model prediction control method based on disturbance observation. According to the method, a state observer is added inan algorithm process, uncertainty interference in a control loop serves as a variable, and the variable is estimated by the state observer and compensated in a prediction model. The method specifically comprises the steps of 1, adding uncertainty interference as a variable into a prediction model of the energy storage converter, and expanding a state space to obtain a system prediction model containing disturbance quantity; and 2, adding a feedback gain matrix on the basis of the rewritten system prediction model to construct a disturbance observer for estimating the disturbance quantity. According to the improved finite set model prediction control method, the influence of disturbance quantity on the system can be effectively solved, and the performance of the energy storage converter canbe further optimized.

The invention discloses a finite control set model predictive contour control method suitable for a double-axial or tri-axial feed driving system. On the basis of unified modelling, unified control architecture of the double-axial or tri-axial feed driving system for finite control set model predictive control is provided; output information of various axes are interacted; furthermore, various axis loop controllers are integrated; simultaneously, under the control architecture, a compact non-cascade predictive controller is designed; a unified value function is established by taking the contour error, the running performance of a motor and the current amplitude limitation as evaluation indexes; and thus, multi-variable cooperative optimization control is realized. Different from the traditional contour control strategy, a finite control set model predictive control strategy can perform predictive control before the contour error occurs; furthermore, the dynamic response speed and the contour precision at the position of a trajectory turning point can be increased; and simultaneously, the method in the invention has the advantages of being intuitional to model, simple in structure and the like.

The invention discloses a novel yaw control method based on wind direction prediction. The method comprises the following steps of (1) establishing an ARIMA-KF prediction model for predicting the winddirection; and (2) performing yaw control based on an MPC of a finite control set. Compared with an existing industrial yaw control method, the novel yaw control method based on wind direction prediction has smaller yaw errors, and therefore the maximum wind power obtaining capacity is improved.

The invention discloses a finite control set model prediction control method considering switching frequency optimization. The method comprises: firstly, detecting a system state variable, and using an integrator for obtaining the continuous period number of a control signal; secondly, predicting the future state of the system and the continuous period number of the control signals by using the system state prediction model and the continuous period number prediction model of the control signals; and finally, evaluating the voltage vector of the converter by using the value function combined with the control signal constraint term, selecting the voltage vector which minimizes the value function as the optimal voltage vector, and acting on the converter. According to the finite control set model predictive control algorithm considering switching frequency optimization, the switching frequency of a system is controlled through a method for predicting and constraining the number of duration periods of control signals, and the defect that the switching frequency is not fixed in a traditional finite control set model predictive control algorithm is overcome.

A multistep finite control set model predictive control method for linear induction machines is provided, and the method belongs to a control technology field for linear induction machines. The method specifically includes the following steps: collecting a primary phase current of a linear induction machine in a three-phase coordinate system; solving a multistep reference voltage vector sequence by iteration according to a current value; keeping only two non-zero voltage vectors and one zero voltage vector that are closest to a reference voltage vector in each predictive step; and further eliminating a voltage vector sequence having a large cost function value through dynamic online comparison with a cost function value.