525results about How to "Small steady state error" patented technology

The invention discloses a robust dicyclic photovoltaic grid-connected control method based on power feedforward, which mainly comprises three parts: proportion integration (PI) control of exocyclic voltage, dead-beat control of endocyclic robust predictive current and power feedforward control, wherein the exocyclic PI control of the voltage is used for stabilizing the capacitive voltage of a direct-current side; the dead-beat control of the endocyclic robust predictive current is used for carrying out linear prediction on the voltage of a power grid at a next control period and carrying out non-linear prediction on grid-connected current by advanced control so as to obtain the command value of the grid-connected current at the next period; and then, PWM (pulse-width modulation) and grid-connected control are realized by the dead-beat control. According to the robust dicyclic photovoltaic grid-connected control method based on the power feedforward, a photovoltaic grid-connected inverter has higher robustness, wider stability margin and quicker dynamic response, and the requirement of grid-connected running of an inverter is better met.

The invention belongs to the field of spacecraft control and relates to a fuzzy singular perturbation modeling and robust attitude control method for complex flexible spacecraft, namely a robust combined control method for fusing static output feedback control and output integration. The method comprises the following steps of: establishing an uncertain continuous fuzzy singular perturbation model and a standard discrete fuzzy singular perturbation model according to a dynamic model and a kinematic model of the spacecraft in combination with fuzzy logic and singular perturbation technology; and designing a robust controller combined by a static output feedback controller and an output integrator by a spectral norm and linear matrix inequality (LMI) method and resolving a group of LMIs which are unrelated to a perturbation parameter so as to obtain a controller parameter and solve an ill-conditioned problem caused by the perturbation parameter and the problem of difficulty in selection of an initial value in an LMI resolving static output feedback controller gain method. Through the method, flexible vibration and external interference can be overcome effectively, and control effects such as high response speed, high attitude control accuracy, high anti-jamming capability and high robust performance are achieved.

The invention relates to a two-stage photovoltaic grid-connected control system based on the combination of pole allocation and repetitive control, which can invert the direct current output by a photovoltaic cell into alternating current well and transmit the alternating current to a power system, so that the harmonic wave content is low, the power supply quality is good, the utilization ratio of a system is high, the stability of the system can be improved to a certain extent and the properties of the whole photovoltaic system are improved. The two-stage photovoltaic grid-connected control system based on the combination of pole allocation and repetitive control has the advantages that: (1) due to the adoption of numerical control, the antijamming capacity is high and the system can achieve high precision and stability; (2) the system has clear assignment, obvious control effect, reliability and high robustness, wherein a preceding-stage Boost converter can realize maximum power tracking; and a last-stage inverter achieves direct current side voltage stabilization and grid-connected inversion; and (3) a control algorithm is advanced, wherein a dead zone effect of the inverter and the harmonic wave caused by partial non-linear loads are avoided by a repetitive control technique; and precise control is realized through the state feedback-based pole allocation.

A double-ring dead-beat prediction control method for a permanent magnet synchronous motor based on disturbance estimation compensation comprises the following steps: establishing a discrete current prediction model of the permanent magnet synchronous motor, and designing a dead-beat current prediction controller; designing a sliding mode disturbance observer to estimate stator current and parameter disturbance; designing a dead-beat speed prediction controller; and designing a sliding mode disturbance observer to observe and compensate the load torque. According to the invention, under the condition that motor model parameters are not matched, the method achieve the accurate current control; under the condition that the dead-beat speed prediction controller is sensitive to load change, the method achieves the improvement of the dynamic and static performance and the anti-disturbance performance of the speed outer ring through load torque observation and compensation.

The invention discloses a control system of a high frequency switching power supply for a Cz silicon single crystal furnace and a control method. The control method includes the steps of combining self-adaptive fuzzy control and sliding mode variable structure control, and aiming at a high-frequency switch heating electric power for the Cz silicon single crystal furnace to design a power controller based on a self-adaptive fuzzy control and sliding mode variable structure control method. The control system of the high frequency switching power supply for the Cz silicon single crystal furnace and the control method play respective advantages of fuzzy control and sliding mode variable structure control, further improve dynamic performance of the system, have good robustness for input voltage or load disturbance, and relieve or avoid vibration which generally happens to a sliding mode.

The invention relates to an anti-interference attitude control method suitable for a miniaturized unmanned aircraft. The method comprises the following five major steps: decomposing an aircraft model into a determination part and a disturbance term; according to a decomposition model of an aircraft, designing a disturbance observer based on flight state estimation; according to the determination part of the aircraft model, designing an attitude controller, adding an anti-disturbance integrator, and forming an integration backstepping attitude controller; replacing a disturbance item in the integration backstepping attitude controller with the output of the disturbance observer to obtain an anti-interference attitude controller; and performing stability analysis on the anti-interference attitude controller to obtain a control parameter value criterion. Compared to the prior art, the anti-interference controller can rapidly reacts to external disturbance and has quite high robustness for continuous and time-varying disturbance; and the external disturbance can be inhibited, the control performance in a severe environment is improved, unfavorable influences brought by an inaccurate mathematics model are reduced, the modeling workload is decreased, and the parameter setting of the anti-interference attitude controller is convenient.

The invention relates to a dual-motor energy-saving anti-backlash control method and belongs to the technical field of electromechanical control. A nonlinear dual-motor system is changed into an approximate linear system by applying a bias torque and rotating speed negative feedback; in addition, a real-time bias torque is designed to save energy to the greatest extent on the basis of ensuring good tracking effect. A closed-loop control is formed from speed and acceleration feedback of the motor, so that the size of the bias torque changes with the state of the system, namely a large bias torque is applied at the beginning and during the direction changing process, and a small value is needed to keep the state due to no need of the bias torque in stable operation. In order to solve the design problems of the dual-motor system about bias torque parameters and a proportion integration differentiation (PID) controller parameters, a plurality of controller parameters are simultaneously optimized by adopting a particle swarm algorithm. By adopting the dual-motor energy-saving anti-backlash control method, the problem about an optimization design of the controller of the dual-motor drive system is solved, and meanwhile, the effects of quick tracking of an input signal by the system, a small steady state error, synchronization of double motors, backlash removal and reduction of energy consumption are ensured.

The invention discloses an anti-backlash and synchronization control method for a dual-motor servo system, relating to a tracking, synchronizing and anti-backlash comprehensive control method for a dual-motor servo system and belonging to the technical field of motor control. The implementation method of the invention comprises the following steps: analyzing a dual-motor servo system with backlash; building a state-space equation of the system by using a dead zone model of the backlash; designing a tracking controller by using a robust backstepping control method; respectively designing a synchronization controller and an anti-backlash controller by using the robust backstepping control method based on the tracking controller; and introducing a transfer function for the anti-backlash controller and the synchronization controller, applying the anti-backlash controller to make up for backlash when the backlash is about to appear and carrying out synchronization control when no backlash appears, thus ensuring the tracking, synchronizing and anti-backlash control of the dual-motor servo system. The technical problem to be solved in the invention is to eliminate the influence of backlash nonlinearity and ensure the synchronization of motors under the premise of realizing load tracking.

The invention discloses a tension roll control device for a plate and strip processing line and a tension control method, belonging to the field of tension control of tension rolls on the plate and strip processing line in the metallurgical industry. The tension roll control device comprises a tension roll group, an auxiliary roll frequency converter and a main roll frequency converter, and further comprises an auxiliary roll speed encoder, a main roll speed encoder, a load distributor, a tension regulator, a feedforward compensation unit and a tensiometer, wherein two ends of the load distributor are respectively connected with the auxiliary roll frequency converter and the main roll frequency converter; the auxiliary roll frequency converter comprises an auxiliary roll rotation speed control unit and an auxiliary roll torque control unit; and the main roll frequency converter comprises a main roll rotation speed control unit and a main roll torque control unit. The tension roll control device has the advantages of high control response speed and high control precision. A control method of the tension roll control device comprises the steps of: (1) main/slave load distribution for the tension rolls; (2) complex tension control of the tension rolls; and (C) dynamic compensation. The method has the advantages of small steady state error of a torque loop, short anti-disturbance recover time, constant rotation speed and good anti-disturbance performance.

The invention belongs to the technical field of wind power generation, and discloses a comprehensive control system adopting a doubly-fed wind generator participated in power grid primary frequency modulation. The control system comprises a rotor rotary speed control module, a simulation inertia control module, a droop control module, a rotary speed protection and power determination module and apitch angle control module. After the wind generator is participated in frequency modulation, the power grid inertia is equivalently enlarged, so that the doubly-fed asynchronous wind generator can have inertia response on the power grid frequent as the conventional synchronous generator, thereby lowering change rate of the power grid frequency; and by controlling the rotary speed and the pitch angle, the wind generator output is lowered, so that the wind generator has certain active backup capacity to be participated in primary frequency modulation, thereby lowering steady-state error of thefrequency.

The invention discloses a self-adaptive fuzzy control method for an active power filter based on feedback linearization, relates to the technical field of an active power filter, and respectively designs independent self-adaptive controllers aiming at a current loop and a voltage loop. As the current loop adopts the self-adaptive fuzzy controller for the active power filter based on the feedback linearization, the feedback linearization theory, fuzzy control, sliding mode control, self-adaptive control and Lyapunov stability theory are comprehensively utilized, and on the basis of ensuring the global stability, the purpose of harmonic compensation is realized. As the voltage loop adopts the self-adaptive fuzzy PI (process integration) control, according to the fuzzy rule, the control strategy can automatically adjust the PI parameter, strengthen the robustness of the system, improve the dynamic performance of the system, and ensure the tracing to the command voltage.

The invention discloses an adaptive beamforming method based on a convex combination. The method mainly comprises the following steps: an array antenna receives a signal, a least square adaptive filter and a variable step size adaptive filter are constructed, the weight updating formulas of two adaptive filters are subjected to convex combination to obtain the weight of a combined filter, the received signal is inputted to obtain a best weight vector through a convex combination filter, and the best weight vector and a scanning vector are subjected to multiplying to obtain an output signal of the antenna. The method has the advantages of fast convergence speed and small steady-state error, and the mobile communication has the advantages of high signal to noise ratio and good stability.

The invention discloses a variable-step self-adaptive echo interference cancellation method based on preliminary channel estimation, which comprises a preliminary channel estimation process based on correlation detection, a channel tracking process based on a variable-step self-adaptive algorithm and an echo cancellation process, wherein the initial characteristic parameters of the echo channel are acquired in the preliminary channel estimation process; the precise channel tracking process is completed according to the channel characteristic parameters acquired by the channel preliminary estimation process; and the extraction of useful signals is completed in the echo cancellation process. The invention is suitable for processing the problems of channel estimation, channel identification,channel tracking and echo interference cancellation in time-invariant channels and time-variant channels. The method can quickly capture the characteristics of the echo channel, track the variation process of the channel in real time, and accurately restore the signals submerged in echo interference noise in real time.

The invention provides a power electronic transformer enabling the high quality of electric energy output, and a control method thereof. A topologic structure of the power electronic transformer includes an input stage, an intermediate isolation stage and an output stage. The output stage is an inverter of a three-phase four-leg structure, wherein the previous three phase legs adopts a dual-closed loop control strategy based on an output voltage outer loop of a PIR controller and an inductance current inner loop of a PI controller, and the fourth leg adopts a neutral current independent control method based on proportion resonance. The frequency characteristic curve and root locus of the frequency domain theory and other relevant methods are utilized to carrying out frequency division setting for dual-closed loop PIR-PI controller parameters. Therefore, the stability is effectively improved, and stable errors and robustness requirements of a system are also taken into consideration.

The disclosed filter includes active power filter (APF) and passive filter (PF). Output of APF is connected to primary side of isolating transformer. Being connected to series resonance circuit in parallel, the isolating transformer is connected to PF in series, and then connected to electric network. Steady state error of APF is lowered through iterative control algorithm of improper integral. Result output from the control algorithm is as equivalent control in slipform variable structure control, realizing combination of two methods so as to form triplet variable control structure. Comparing with slipform variable structure control or iterative control of improper integral adopted in solely, the invention possesses features of quicker responsibility and smaller steady state error.

The invention discloses a permanent magnet synchronous motor speed control system and method for an electric vehicle. The method comprises the steps of obtaining a q-axis desired current according to a designed fuzzy adaptive sliding-mode speed controller, and setting the d-axis reference current as 0; according to a disturbance value feedback compensation observed by a designed disturbance extended state observer, using the q-axis current output from the fuzzy adaptive sliding-mode speed controller as the q-axis input of a dq-axis internal mode current controller; using the difference of a d-axis feedback current value and the given d-axis current value 0 as the d-axis input of the dq-axis internal mode current controller; obtaining ud and uq after the processing by the dq-axis internal mode current controller, and finally outputting the driving voltage currently operated by the permanent magnet synchronous motor through the vector-controlled inverse park conversion, the SVPWM and an inverter. The method increases the response speed and the anti-disturbance performance of the permanent magnet synchronous motor for the electric vehicle, avoids an overshoot phenomenon, reduces system buffeting, and enhances system robustness.

The invention discloses a method for controlling rotor current of an AC excitation asynchronous doubly-fed induction generator (DFIG) without time delay. The method comprises acquiring a three-phase rotor current signal to perform rotational coordinate conversion to obtain rotor current feedback quantity in a positive rotation synchronous rotating coordinate system, compared with the rotor current command in the same coordinate system, inputting the error signal to a proportion-integral regulator for regulation, performing feedback compensation and decoupling to obtain rotor reference voltage in the positive rotation synchronous rotating coordinate system, converting to the rotor reference voltage for space vector pulse width modulation in a rotor coordinate system, and generating a switching signal for power devices of a rotor side transformer to control on-line operation of DFIG . The inventive method does not require performing positive and negative sequence decomposition of rotor current neither under balanced network voltage nor under imbalanced network voltage, and does not cause decomposition delay, so as to realize enhanced control target of the power generation system under imbalanced network voltage and effectively improve the uninterrupted operation (passing through) ability of the power generation system under network failure.

The invention discloses an asymmetry coordination direct power control method of a double-fed asynchronous wind power generation system, which adjusts the stator electromagnetism and the reactive power as well as active power and reactive power of a grid side convertor of a double-fed asynchronous generator through a proportional resonance regulator consisting of a proportional regulator and two resonance regulators so as to effectively control the operation sate of the double-fed asynchronous generator and the grid side convertor under the condition without positive sequence and negative sequence current quantity decomposition. The invention can realize the integral optimized control effect of the double-fed asynchronous wind power generation system under the condition of asynchronous failures of an electric fence, eliminates total active and reactive power, electromagnetic torque, and DC bus voltage fluctuation of the doublefed asynchronous wind power generation system because of asymmetrical voltage of the electric fence, effectively improves the operation control property of the double-fed asynchronous wind power generation system under the condition of the voltage failure of the electric fence, and ensures the electric energy quality of power supply and the operation stability and the operation safety of an electricity system.

The invention discloses an automated vehicle longitudinal control method based on movement mode judgment. The automated vehicle longitudinal control method based on movement mode judgment is applied to an unmanned vehicle provided with an automatic driving instrument, a GPS/INS positioning system and an industrial personal computer. The automated vehicle longitudinal control method based on movement mode judgment is characterized in that the relative relation between the actual speed and the expected speed of the unmanned vehicle is firstly analyzed, and a movement mode state value of the unmanned vehicle is determined; on the basis that a movement mode of the unmanned vehicle is determined, a control algorithm corresponding to the movement mode is executed to control the vehicle speed so that longitudinal control of the unmanned vehicle can be achieved. By means of the automated vehicle longitudinal control method based on movement mode judgment, longitudinal speed control of the unmanned vehicle is smoother and more comfortable while tracking precision can be guaranteed, and the control process more conforms to the driving habit of humans.