162 results about "Closed-loop transfer function" patented technology

An automated tuning method of a large-scale multivariable model predictive controller for multiple array papermaking machine cross-directional (CD) processes can significantly improve the performance of the controller over traditional controllers. Paper machine CD processes are large-scale spatially-distributed dynamical systems. Due to these systems' (almost) spatially invariant nature, the closed-loop transfer functions are approximated by transfer matrices with rectangular circulant matrix blocks, whose input and output singular vectors are the Fourier components of dimension equivalent to either number of actuators or number of measurements. This approximation enables the model predictive controller for these systems to be tuned by a numerical search over optimization weights in order to shape the closed-loop transfer functions in the two-dimensional frequency domain for performance and robustness. A novel scaling method is used for scaling the inputs and outputs of the multivariable system in the spatial frequency domain.

A fast and reliable technique for tuning multivariable model predictive controllers (MPCs) that accounts for performance and robustness is provided. Specifically, the technique automatically yields tuning weights for the MPC based on performance and robustness requirements. The tuning weights are parameters of closed-loop transfer functions which are directly linked to performance and robustness requirements. Automatically searching the tuning parameters in their proper ranges assures that the controller is optimal and robust. This technique will deliver the traditional requirements of stability, performance and robustness, while at the same time enabling users to design their closed-loop behavior in terms of the physical domain. The method permits the user to favor one measurement over another, or to use one actuator more than another.

A system, method, and apparatus are arranged to provide small-signal compensation in a switching regulator that includes an inductor. A zero adjustment circuit is included in the system to introduce at least one zero in the closed-loop transfer function associated with the regulator. The zero adjustment circuit is responsive to a measurement signal, which is associated with one or more measured parameters associated with the inductor. By changing the location of at least one zero in response to the measurement signal it is possible to dynamically change the compensation based on variations in the inductance of the inductor. The zero adjustment circuit may be provided as a portion of the controller block of the regulator, or as a separate feedback circuit. The zero adjustment circuit can be implemented digitally as a portion of a DSP block, or as an analog function as may be desired in a particular system.

The invention particularly relates to a design and setting method for an active disturbance rejection control system of a time delay system. According to the method, based on the active disturbance rejection technology, firstly, complex controlled objects are fit into a one-order inertial element plus dead time delay mathematic model, meanwhile, time delay comes down to the disturbance quantity, a time delay reduction linear extended state observer is applied to estimation of unknown total disturbance including the time delay, active compensation for the influences of the total disturbance on the system is achieved, the time delay system is restored into a system in an integrator tandem type in an ADRC standard, and then compensation for the time delay system is achieved; finally, a closed-loop transfer function of the system is deduced, a dead time delay link in a characteristic equation is eliminated, and the numerical relationship between an ADRC single-parameter setting formula with universality and adjustable parameters is correspondingly provided. The simulation result verifies that designed practical ADRC has good stability, rapidity, accuracy and disturbance rejection.

The invention discloses a method for realizing a software phase-locked loop with an unfixed sampling frequency. The method comprises the following steps: firstly adopting an analog phase-locked loop digital controlled oscillator of the DSP period counter to obtain digital controlled oscillator output signals; then working out the phase error between the mains voltage and a reference signals in the DQ-transformation phase demodulation mode by using the digital controlled oscillator output signals as the reference signals; and establishing a closed loop transfer function secular equation of a phase-locked loop system and determining the parameters of the designed loop filter based on the digital controlled oscillator output signals and the phase error between the mains voltage and the reference signals. The invention can maintain the fixed number of the sampling points in the primitive period, and is used for repeatedly controlling various grid-connected converting devices, such as active electric filters, new energy-powered grid-connected converters and the like. By adopting the DQ-transformation phase demodulation mode, the invention can well inhibit the harmonic and unbalanced mains, resist the fluctuation of the mains voltage, and ensure the reliable operation of the phase-locked loop under the conditions of multiple mains voltage zero passage, voltage harmonics, voltage fluctuation and mains voltage imbalance.

An automated tuning method of a large-scale multivariable model predictive controller for multiple array papermaking machine cross-directional (CD) processes can significantly improve the performance of the controller over traditional controllers. Paper machine CD processes are large-scale spatially-distributed dynamical systems. Due to these systems' (almost) spatially invariant nature, the closed-loop transfer functions are approximated by transfer matrices with rectangular circulant matrix blocks, whose input and output singular vectors are the Fourier components of dimension equivalent to either number of actuators or number of measurements. This approximation enables the model predictive controller for these systems to be tuned by a numerical search over optimization weights in order to shape the closed-loop transfer functions in the two-dimensional frequency domain for performance and robustness. A novel scaling method is used for scaling the inputs and outputs of the multivariable system in the spatial frequency domain.

The invention discloses a parameter tuning method of a damping controller of a wind farm side based on a wide area measurement system signal, and can effectively inhibit the interval low-frequency oscillation in a system, improve a transmission capacity of a call wire, replace a traditional synchronous generator PSS (Power System Stabilizator) and improve the voltage control. The parameter tuning method comprises the following steps of: 1) adding an excitation signal at the input end of the system and carrying out signal collection at the output end for system identification; 2) utilizing a Prony analysis method to carry out identification on a power transmission system containing a double-fed wind electric field and determining an open-loop transfer function which is not introduced with an additional damping control; 3) on basis of the step 2), utilizing a retention index to select a feedback signal utilized by the additional damping control and a mounting position of the additional damping control; and 4) on basis of the steps 2) and 3), utilizing the open-loop transfer function of the system to tune phase compensation link parameters in an additional damping control link; and drawing a root locus picture of a closed-loop transfer function and determining a gain value K of an additional damping controller.

The invention discloses a method for determining the equivalent aeroservoelasticity (ASE) robust stability of a statically unstable aircraft through a flight test, which is used for solving the technical problem of large modeling errors of the conventional flight test determination method. The technical scheme is that: a closed loop transfer function frequency characteristic matrix of a multi-loop system of the statically unstable aircraft can be obtained through a sweep frequency flight test; a relational expression between a closed loop transfer function and ASE stability is established according to a corresponding relation between the closed loop transfer function and an open loop transfer function; and the closed loop transfer function frequency characteristic matrix of the system is subjected to characteristic decomposition, and a multi-loop stability margin analysis scalar equation is obtained according to the critical stability condition of the system, so that the ASE stabilityof the whole loop is calculated, and problem difficulty is greatly simplified.

The invention relates to the technical field of spacecraft control and particularly discloses an integrated analyzing and setting method for control parameters of a three-loop automatic pilot. The integrated analyzing and setting method comprises the following steps of: firstly, establishing a control loop model of the three-loop automatic pilot; secondly, setting a pitching motion relative damping coefficient after compensating an attitude angular velocity feedback circuit to acquire an attitude angular velocity control parameter and the open-loop cross-over frequency of the attitude angular velocity feedback circuit; thirdly, acquiring an open-loop gain system of a control system according to an open-loop transmission function of the control system and acquiring a closed-loop transmission function which is inputted to a guidance spacecraft by an overload instruction after correction and is outputted in an overload manner; and fourthly, acquiring the attitude angular velocity control parameter, an overload feedback control parameter and an overload instruction correction parameter. According to the integrated analyzing and setting method, the solving of a nonlinear equation is avoided; in addition, attitude stability and attitude control precision of the guidance spacecraft can be maintained by the acquired parameter under various single deviations and combined deviation and the balancing state of the spacecraft required by the guidance instruction is quickly realized.

For runout compensation in a data handling system, a servo feedback loop is configured to control a head position relative to a corresponding disc surface. Operation of the feedback loop is complicated by a repeatable error in the head position having energy at harmonics of the spindle rotation frequency. Also, the feedback loop has a gain with a frequency sensitivity in a target frequency range. A feedforward controller generates an output injected into the feedback loop based on an error-indicative input. This defines a feedforward closed-loop transfer function, between the loop output and the feedforward controller input. The feedforward controller prevents the frequency sensitivity from substantially varying the feedforward closed-loop transfer function gain and phase within the target frequency range, thus reducing computational burden.

The invention discloses a method for determining the equivalent aeroservoelasticity (ASE) robust stability of a statically unstable aircraft through a flight test, which is used for solving the technical problem of large modeling errors of the conventional flight test determination method. The technical scheme is that: a closed loop transfer function frequency characteristic matrix of a multi-loop system of the statically unstable aircraft can be obtained through a sweep frequency flight test; a relational expression between a closed loop transfer function and ASE stability is established according to a corresponding relation between the closed loop transfer function and an open loop transfer function; and the closed loop transfer function frequency characteristic matrix of the system is subjected to characteristic decomposition, and a multi-loop stability margin analysis scalar equation is obtained according to the critical stability condition of the system, so that the ASE stability of the whole loop is calculated, and problem difficulty is greatly simplified.

A mass flow controller having a feedback controller gain, comprises: a sensor configured so as to sense the flow of fluid through controller; a valve arranged so as to adjust the flow of fluid through the controller; and a processor configured so as to controlling the valve as a function of the flow of fluid sensed by the sensor. The sensor and valve are arranged within a feedback system, and the processor updates the feedback controller gain in real time based on the ratio of at least one calibration gas parameter to at least one operating gas parameter, such that the closed loop transfer function of the feedback system remains substantially constant regardless of operating conditions so as to have a consistent control performance at different operation conditions from the calibration condition.

The invention discloses a method for designing stability parameters of a self-adapting filter of a self-balancing system of a magnetic suspension rotor. The method comprises the following steps of establishing a radial rotation dynamics differential equation model of the self-balancing system of the magnetic suspension rotor with a gyroscopic effect; converting a real coefficient bivariate gyroscopic coupling system into a complex coefficient univariate equivalent system through complex transformation; calculating a closed-loop transfer function of the complex coefficient univariate equivalent system; determining a start angle range of a root locus, which meets the stability requirement of the self-balancing system, at a critical stable point of an imaginary axis; resolving a stability parameter intersection of the self-adapting filter; finally, determining the stability parameters of the self-adapting filter. While the rotor speed is estimated and tracked in real time so as to improve the self-balancing precision, the stability of the self-balancing system of the magnetic suspension rotor with the gyroscopic effect within a full speed range is ensured. The method disclosed by the invention is simpler and more convenient than other methods, and is especially suitable for practical magnetic suspension rotor systems.

The invention discloses a parameter setting method for a double-closed-loop vector control PI regulator of a permanent magnet synchronous motor. A current inner loop system is corrected into a first-order system by utilizing a pole-zero cancellation principle in a current loop closed-loop transfer function; a proportional coefficient and an integral coefficient of a current loop PI regulator are obtained through the current loop closed-loop transfer function; when two constraint conditions of enabling the slope at a cut-off frequency of a speed loop open-loop transfer function to be -20 dB / decand obtaining the maximum phase angle margin are met, a proportional coefficient and an integral coefficient of a speed loop PI regulator are determined; and parameters of the speed loop PI regulatorare obtained. An automatic control related theory is combined, and a theoretical basis is provided for setting the PI parameters; change relations between the PI parameters, and a motor parameter-current loop bandwidth and a system performance index-damping factor are revealed; the PI parameters can be set for different motor systems more flexibly and accurately; and therefore, the universality is high.

The invention relates to a power system stabilizer (PSS) configuration method in coordination with a low-excitation limiting function. The method is characterized by comprising steps: a generator typical leading phase operation working condition point set based on a low-excitation limiting boundary line is set; an open-loop transfer function G<X>(s) for electromagnetic torque increment signals generated by the traditional power system stabilizer PSS1 through an excitation link when low-excitation limiting does not act in relative to PSS1 input signals is determined; an open-loop transfer function G'<X>(s) for electromagnetic torque increment signals generated by the newly-added power system stabilizer PSS2 through an excitation link when low-excitation limiting acts in relative to PSS2 input signals is determined; and by using the transfer function G<X>(s) and the transfer function G'<X>(s), an optimal mathematical model for a lead-lag link time constant of the PSS2 is built and solved. The configuration method of the invention has the advantages that comprehensive factors are considered; the operation is simple and convenient; the practicability is strong; and the deteriorated dynamic stability of the power system caused as the low-excitation limiting acts can be effectively solved.

The invention relates to a weak power grid source load impedance model analysis method of a grid-connected power generation system, and relates to the technical field of power grids. The technical problem that the existing method is not suitable for a weak power grid is solved. The method comprises the steps that a grid source load impedance model is defined for the grid-connected power generation system, wherein the model is combined with grid-connected inverter common coupling point voltage, alternating current power grid line impedance, alternating current power grid load impedance, alternating current power grid equivalent voltage, alternating current power grid equivalent current source and alternating current power grid access current of the grid-connected power generation system; the assumption that the load of an alternating current power grid is a resistive inductive load and the line impedance of the alternating current power grid is resistive inductive line impedance is carried out, so that an open-loop transfer function and a closed-loop transfer function of the grid-connected power generation system under double-loop control are acquired; and according to the acquired open-loop transfer function and the closed-loop transfer function, the grid-connected power generation system is analyzed. The method provided by the invention is suitable for analyzing the grid-connected power generation system under the weak power grid.

The invention discloses an inertia identification and load torque observation-based speed loop response improvement method. A motion curve is fit by adopting motion information of constant-torque acceleration and free deceleration of a motor through a least square method to obtain rotational inertia and friction information of a servo system offline. A theoretical parameter setting value of a speed PI adjuster can be obtained on the basis of rotational inertia information obtained through offline identification according to a speed closed-loop transfer function optimization theory, so that blind adjustment of a PI parameter when the rotational inertia of a system is unknown is avoided, and the PI parameter is finally adjusted by combining the practice to set a driver to the optimal performance.

The invention discloses a method for setting parameters of a speed governor of a direct current delivering-out system of a hydroelectric generating unit. The method comprises the following steps of establishing a model for analyzing stability of the speed governor of a water turbine; obtaining a transfer function of a power generator and an external system thereof, a transfer function of a linearized model of the water turbine, and a transfer function of a linearized model of the speed governor; solving a closed-loop transfer function corresponding to the model for analyzing the stability of the speed governor of the water turbine, and a closed-loop characteristic equation of the speed governor, and utilizing Routh stability criterion to obtain a transient descending rate value range and a buffer time constant value range for stabilizing a speed governing system; performing time domain simulation in the transient descending rate valve range and the buffer time constant value range for stabilizing the speed governing system, so as to obtain optimum parameters of the speed governor of the water turbine. The method has the advantages that by adopting the model for analyzing the stability of the speed governor of the water turbine, and combining the Routh stability criterion and the time domain simulation, the optimum parameters of the speed governor of the water turbine are finally obtained, and the robustness is stronger; the method is widely applied to the field of power.

The invention discloses a permanent magnet synchronous motor self-adaptive identification control method comprising the following steps that the dynamic model of the vector control system of a permanent magnet synchronous motor is established under a dq coordinate system, and decoupling control is performed on the component of stator voltage in the dq coordinate system; a simplified state space model of the permanent magnet synchronous motor is established; parameter identification is performed on the undetermined parameters in the simplified state space model of the permanent magnet synchronous motor so that stable motor identification parameters are obtained; an accurate model of the permanent magnet synchronous motor is established according to the stable motor identification parameters, and a speed ring closed-loop transfer function is calculated; a reference model of the permanent magnet synchronous motor is constructed according to the speed ring closed-loop transfer function and the static and dynamic performance indexes of the vector control system; and self-adaptive control rate of the permanent magnet synchronous motor is derived according to the reference model of the permanent magnet synchronous motor and the speed ring closed-loop transfer function after identification. A speed ring is enabled to have better stability, anti-interference capability and control precision.

The invention discloses a composite layer anti-interference control method for a deformable unmanned aerial vehicle. The method comprises the steps that an unmanned aerial vehicle with variable sweepand variable span. The method comprises the steps that the unmanned aerial vehicle with variable sweep and variable span is taken as a study object, and firstly, a nonlinear model of the unmanned aerial vehicle is subjected to Jacobian linearization; external gust interference and equivalent interference brought by parameter perturbation are considered, and a multi-cell LPV system model of the deformable unmanned aerial vehicle containing multiple interference kinds is built; then regarding a constant value and slow varying interference, an interference observer meeting the H8performance indexis designed for compensation, and an H8control law is designed for optimizing a closed loop transfer function regarding the conditions of not representing dynamic characteristics of the interferenceobserver and facing L2 bound norm bounded interference to inhibit bounded interference; finally, and the interference observer is combined with the H8control law to construct a composite layer anti-interference controller; the method has the advantages that the method of sorting and treating multiple interference kinds for the deformable unmanned aerial vehicle, and the method can be applied to interference control of composite layers of other motion bodies with more complex system models.

The invention discloses a wind power station subsynchronous resonance suppression method and system, the wind power station at least comprises: a plurality of wind turbines, a plurality of transformers and wind power station lines, the wind power station is characterized in that: acquiring voltage signals and current signals of wind power station lines, resistance and inductance of the plurality of wind turbines, resistance and inductance of the plurality of transformers, resistance and inductance of the wind power station lines and current signals actually outputted from the subsynchronous suppression system to a power grid; performing filtering processing on voltage signals and current signals of the wind power station lines, obtaining subsynchronous frequency signals, according to the subsynchronous frequency signals, the resistance and the inductance of the plurality of wind turbines, the resistance and the inductance of the plurality of transformers and the resistance and the inductance of the wind power station lines, obtaining wind power station closed loop transfer functions, and according to the current signals actually outputted from the subsynchronous suppression system to a power grid, optimizing the attenuation rate of the closed loop transfer functions under different zero points through optimizing parameters. According to the invention, the stability of the wind power station can be effectively improved.

The invention discloses a harmonic instability analysis method for a double-fed fan grid-side converter, comprising the following steps: firstly, building a harmonic model for the double-fed fan grid-side converter; secondly, only considering influence of a current control loop and grid-side impedance, and building an output admittance small signal model under a d axis according to the model in the step 1; thirdly, building a return ratio matrix under the influence of the d axis according to the model in the step 2; fourthly, obtaining an output impedance closed loop transfer function under adq axis and a return ratio matrix thereof according to the model in the step 2; and fifthly, respectively extracting characteristic values of the return ratio matrixes obtained in the step 3 and the step 4, and carrying out harmonic instability analysis on each parameter according to a generalized Nyquist criterion. The method disclosed by the invention can simply and visually judge and control influence of parameters as well as conversion trends of inductances and resistances at a grid side and an alternating current side on system stability.

The invention belongs to the technical field of controller optimization, and relates to a servo system controller optimization method based on an expected closed-loop transfer function. The method aims to solve the problems that because the quantitative relation between the frequency response index and the controller parameters of a present controller is not established and whether the design result is satisfactory or not is determined by experience of designers to a great extent, it can not be guaranteed that the performance of a closed-loop system is the optimal and 'double-ten' controller optimization methods are rarely reported. The method comprises the steps of firstly, determining the transfer function of a controlled object; secondly, constructing the structural form of the expected closed-loop transfer function; thirdly, establishing the mathematic relations between the expected closed-loop transfer function and the system frequency response index, the shear frequency and the stability margin constraint condition respectively; fourthly, obtaining the optimized parameters of the expected closed-loop transfer function; fifthly, working out the controller.

The invention discloses a heating furnace temperature controller design method based on an improved Dahlin algorithm.For the nonlinear characteristic of a heating furnace, according to the heating furnace temperature controller design method, different temperature set value jump intervals are set according to the size differences of temperature difference jump values of set target temperature and initial temperature, and different expected closed loop transfer functions are set in all the intervals to design a temperature controller.When heating furnace temperature controller design is conducted, the problems that for a traditional Dahlin algorithm temperature controller, the adjusting time is long, and steady state error elimination is slow are considered, the Dahlin algorithm is combined with integral control, special processing is conducted on control quantity limitation, the steady state error is further eliminated, the adjusting time is further shortened, and control over the heating furnace temperature can be achieved more rapidly and accurately.

A mass flow controller having a feedback controller gain, comprises: a sensor configured so as to sense the flow of fluid through controller; a valve arranged so as to adjust the flow of fluid through the controller; and a processor configured so as to control the valve as a function of the flow of fluid sensed by the sensor. The sensor and valve are arranged within a feedback system, and the processor updates the feedback controller gain in real time based on the ratio of at least one calibration gas parameter to at least one operating gas parameter, such that the closed loop transfer function of the feedback system remains substantially constant regardless of operating conditions so as to have a consistent control performance at different operation conditions from the calibration condition.

The invention relates to a method for designing a stabilizer in a transmission shaft system of a double-feed wind turbine generator and the stabilizer. The method for designing the stabilizer in the transmission shaft system of the double-feed wind turbine generator comprises the steps that a complex frequency domain closed-loop transfer function E(s) between an electromagnetic torque increment delta Te and a motor rotating speed increment delta omega g is obtained, the complex frequency domain closed-loop transfer function E(s) is decomposed into E(s)=dH(s), the phase position theta H at the position of the reversing oscillation frequency omega i under the rated operating condition is obtained, the offset angle phi of the stabilizer is determined according to the phase position theta H, and the transfer function Gd(s) of the stabilizer is obtained according to the offset angle phi, and then the stabilizer in the transmission shaft system of the double-feed wind turbine generator is designed. Compared with an existing method for designing the stabilizer, the method for designing the stabilizer in the transmission shaft system of the double-feed wind turbine generator has the advantages that it is guaranteed that the stabilizer has the more effective control performance under the same gain condition, and the method has great significance in reducing torque impact of the transmission shaft system in the transient state, prolonging the mechanical life of the transmission shaft system of the wind turbine generator and improving the reliability of the transmission shaft system of the wind turbine generator.

The invention discloses a flight test robust determination method for the equivalent stability margin of a statically unstable aircraft, which is used for solving the technical problem of large errors of the conventional flight stability margin determination method. The technical scheme is that: a closed loop transfer function frequency characteristic matrix of a multi-loop system of the statically unstable aircraft can be obtained through a sweep frequency flight test; a relational expression between a closed loop transfer function and the stability margin of the system is established according to a corresponding relation between the closed loop transfer function and an open loop transfer function; and the closed loop transfer function frequency characteristic matrix of the system is subjected to characteristic decomposition, and a multi-loop stability margin analysis scalar equation is obtained according to the critical stability condition of the system, so that the phase margin andmagnitude margin of the whole loop is calculated, and problem difficulty is greatly simplified.

The invention provides a method for coating a photoresist film and coating equipment using the method. The method comprises the following steps of (A) according to known parameters of a photoresist and equipment parameters of the coating equipment, obtaining a closed loop transfer function of a control system; (B) according to the closed loop transfer function, performing PID (Proportional-Integral-Differential) control on a BP (back propagation)-based neural network. According to the method for coating the photoresist film provided by the embodiment of the invention, under the condition that a set coating speed of the coating equipment is kept, the thickness of the coated photoresist film can be controlled only by adjusting the flow rate of the photoresist, so that the thickness of the photoresist film is automatically adjusted at the optimal coating speed of the coating equipment, manual adjustment by a worker is not required, the labor is saved, the adjusting and controlling time is quickened, and the working efficiency is improved.

The invention provides a control method for a gas path system of a gas chromatograph. The method includes the steps that an open-loop transfer function of a proportional valve arranged in the gas path system is pre-calibrated through an erected hardware platform for calibration, and a look-up table of amplitude and phase information at different frequencies of the open-loop transfer function of the proportional valve is made; an optimum PID parameter control value in a closed-loop system is set; finally, according to measured gas parameter values, the current gain and the current phase of the open-loop transfer function of the proportional valve are acquired through comparison with the look-up table, and PID parameter values in a control algorithm are corrected through the change of gains and phases. Through the open-loop characteristics of the pre-calibrated proportional valve, PID parameters of the closed-loop system are corrected according to currently-measured gas pressure and flow, and more stable and quicker closed-loop control over gas pressure and flow is achieved within a large application range.