14 results about "Steady state operating point" patented technology

The present application relates to the field of power system stability analysis and control, in particular to a kind of thermal mass energy storage converter broadband oscillation suppression parameter stable domain identification method, comprising the following steps: establish general electric-thermal coupling mechanism model, construct the dynamic differential equation describing the evolution of input electric power and energy storage medium temperature state of converter;Mechanical dynamics equation is constructed;Establish the small signal state space model of whole system, linearization is carried out at steady state operating point and the state space matrix of whole system is derived;Define practical small disturbance stability domain, set the real part decay rate threshold and minimum damping ratio threshold of whole system eigenvalue;Algebraic singularity constraint equation in high-dimensional parameter space is constructed;Solve algebraic singularity constraint equation, establish parameter stable domain.This method avoids the repeated iteration of traditional eigenvalue analysis, can accurately depict parameter boundary, effectively improve the frequency support capability of high proportion of new energy power grid and system robustness.

This invention relates to the field of wind power converter control, and provides a method and system for switching control between black start and islanded operation of a wind power converter. Before responding to a closing command, the method first predicts the new steady-state operating point to be reached after load connection, including steady-state values ​​such as PCC voltage and converter output current, based on the electrical parameters of the load to be connected. Then, it calculates the corresponding state values ​​that the integrators of the voltage and current loop PI controllers inside the converter should possess at the new steady-state operating point. Finally, at the instant the circuit breaker closing signal is issued, these pre-calculated integrator state values ​​are synchronously preset into the controller's integrator. In this way, the controller's internal state is already near the new steady state at the moment of load connection, thus skipping the transient process of response lag and error accumulation in traditional PI controllers, achieving a smooth transition from no-load to loaded, and effectively suppressing voltage and frequency surges during the switching process.

The invention discloses a method for analyzing the influence of heterogeneous micro-grid parameters on system stability in a continuous steady state. The method is specifically implemented according to the following steps: step 1, acquiring steady-state working points of a heterogeneous micro-grid through parameter scanning; step 2, acquiring a low-frequency characteristic value of the heterogeneous micro-grid system in a continuous steady state based on the state space model of the micro-grid; and step 3, obtaining a participation matrix and a participation factor of the heterogeneous micro-grid system, determining a key variable according to the participation factor, and analyzing an influence rule of the parameter on the stability of the heterogeneous micro-grid according to the key variable. According to the method, the problem that in the prior art, a fixed working point is used for representing behaviors in the whole period in a traditional characteristic value analysis method, and consequently analysis is not accurate is solved.

The application discloses an aero-engine thrust fast response redundant control method and system considering combustion delay, and belongs to the technical field of aero-engine control. The method steps are as follows: an open-loop transfer function L of main fuel flow and tail nozzle throat area respectively controlling thrust is established based on a desired thrust closed-loop bandwidth; a decoupling condition between the variable tail nozzle throat area and the thrust is set to eliminate the mutual influence between them; four undetermined RTM controller functions in the transfer function L are solved; the actuator transfer functions of the main fuel flow and the tail nozzle throat area are set as first-order systems for solving; system identification is carried out at an engine steady-state working point to obtain a transfer function of a difference between the main fuel flow and the tail nozzle throat area relative to a steady-state value to a difference between the thrust and the steady-state value; the transfer function L is solved, and then the RTM control is completed according to the transfer function L, so that the fast response control of the thrust is realized. The application solves the key technical problems in the prior art.

The application discloses a power distribution network operation stability evaluation method considering entropy space, constructs a distributed power supply dynamic model, and designs a distributed power supply energy function; based on the distributed power supply energy function, an energy value of a leading unstable balance point is selected as critical energy, and a critical energy surface is fitted; a system entropy index representing power flow balance and static voltage safety of the power distribution network is constructed, the system entropy index is dispersed to a distributed power supply level to obtain a distributed power supply entropy index; a distributed power supply entropy boundary condition is designed, a distributed power supply entropy space representing safety and stability is constructed based on a boundary projection method; energy values of a steady state working point and a given expected accident are quickly solved, and the energy values are quickly positioned in and outside the entropy space; and based on positioning results and the distributed power supply entropy space, the power distribution network operation stability is evaluated. Compared with the prior art, the application evaluates the power distribution network operation stability according to the distributed power supply entropy space, and simplifies a traditional safety and stability evaluation method.

The invention relates to the technical field of power electronics, and particularly provides a harmonic prediction and suppression method for a droop control converter based on a multi-frequency estimator, and the method comprises the steps: obtaining a main circuit parameter, a control parameter and a steady-state working point parameter of the droop control converter; determining a main circuit matrix of a harmonic state space according to the main circuit parameters based on the steady-state working point parameters, and determining a harmonic state space control loop matrix according to the control parameters; splitting by columns according to a target parameter matrix of the main circuit matrix, and separating components related to the switching disturbance to obtain a plurality of parameter sub-matrixes corresponding to the switching disturbance; the control loop matrix is substituted into the parameter sub-matrix, a harmonic state space equation is obtained, a harmonic transfer function matrix is calculated, and the harmonic transfer function matrix is used for conducting harmonic prediction according to the main circuit parameters, the control parameters and the steady-state working point parameters. According to the invention, the harmonic prediction accuracy is effectively improved.

The present application relates to motor variable frequency stable control technical field, especially offshore wind motor electric variable frequency grid-connected large interference stability analysis method and system, method includes: the nonlinear dynamic model of motor and generator set variable frequency system is established;With the steady state operating point of nonlinear dynamic model as the coordinate origin, the operation characteristic space is divided into fuzzy subspace;In each fuzzy subspace, the model is locally linearized, and the TS fuzzy model set is constructed;Based on the TS fuzzy model set, the corresponding quadratic Lyapunov function is constructed, and the maximum attraction domain boundary is solved and projected to generate a two-dimensional stable operation region map;According to the maximum state variable boundary in the map, the output power command of the offshore wind power system controller is adjusted to maintain system stability.Through the present application, the problem that the prior art cannot maintain system stability and equipment damage when the rotating unit variable frequency system is subjected to high-power disturbance is effectively solved.

The application discloses a kind of impedance automation measurement methods of power electronic converter based on real-time simulation platform, including in simulation model, disturbance injection module, data acquisition module, computing flow or time-domain simulation obtains steady state operating point;In disturbance injection module, the parameter that needs to be measured is determined;According to the starting time of measurement, the starting time of the recording wave of data acquisition module in real-time simulation platform, real-time simulation step, sampling factor, storage file size and storage file are determined, and according to the starting time of measurement, the duration of each frequency disturbance, disturbance interval waiting time, the total frequency number of frequency sequence, the total duration of real-time simulation is determined;Injection disturbance, and the voltage and current data set of measured port are obtained;The total frequency number of frequency sequence is calculated impedance value, and full-band impedance characteristic curve is generated.According to the measurement method disclosed in the application, the impedance scanning efficiency is improved, and the new energy equipment impedance is quickly and accurately obtained.

The invention relates to a heating furnace steady state operation point drift detection and positioning method based on multi-source data fusion, and belongs to the technical field of ferrous metallurgy automation control. According to the method, aiming at the problem of steady-state operation point drift in the operation process of the heating furnace, a group of drift sensitive indexes including furnace temperature standardization residual error, furnace temperature drift rate, temperature-energy consistency index and the like are constructed by collecting multi-source data such as strip steel operation speed, furnace temperature of each furnace area, gas flow, air flow, outlet plate temperature and the like; and carrying out smoothing processing by adopting an exponential weighted moving average method, calculating the drift intensity of each furnace area and the overall drift intensity of the plate temperature so as to judge whether steady-state operation point drift occurs or not, and positioning the leading furnace area and the drift direction when judging that the drift occurs. The online monitoring and diagnosis of the steady-state operation point of the heating furnace can be realized, and the operation stability of the heating furnace and the product quality control precision are improved.

The invention discloses a transient state-steady state hybrid control method of a buck converter based on state space switching. The method comprises the steps that firstly, inductive current and output voltage of the step-down converter are sampled and normalized, and the normalized inductive current and output voltage serve as state variables to construct a state space; then, on the basis of the state space, the operation state of the converter is judged according to the switching criterion; finally, when it is judged that the converter is in the load transient state, nonlinear transient control based on the state space is adopted to adjust the inductive current and the output voltage, and the system is made to move towards a target steady-state working point along the average natural track; and when the converter is judged to enter the steady-state operation working area, performing closed-loop regulation on the converter by adopting double-loop proportional-integral linear steady-state control. The problems that the transient response speed of a linear control method is limited and stress constraint and steady-state operation stability of a device are difficult to consider by a nonlinear control method under the load transient condition of an existing step-down converter are solved.

This invention discloses a two-layer optimized economic predictive control method and apparatus for proton exchange membrane fuel cells. The method includes establishing a mechanistic model of the proton exchange membrane fuel cell system, determining the system's control variables, output variables, and external current disturbance signals; an upper real-time optimization layer constructs a steady-state economic index function based on the current external current disturbance signal and the principle of maximizing the system's net output power, solves for the optimal steady-state operating point, and obtains the optimal output variable setpoint; a lower real-time control layer receives the optimal output variable setpoint, solves for the optimal control variable sequence based on the proton exchange membrane fuel cell prediction model, and adjusts the system's control variables to make the system's actual output variable track the optimal output variable setpoint. This invention solves the problem of low system net efficiency caused by prior art that only focuses on the performance of the fuel cell stack while neglecting the power consumption of auxiliary equipment, thus improving the overall operating economy and energy utilization rate of the system.

The present disclosure relates to a kind of AC-DC hybrid micro-grid system stability determination method and device.Wherein, the method includes: establishing the equivalent model of the AC-DC hybrid micro-grid system under synchronous rotation dq coordinate system;Based on mixed potential function theory, generate the nonlinear model of the AC-DC hybrid micro-grid system;The steady-state operating point of the AC-DC hybrid micro-grid system is generated, and the steady-state operating point is generated according to the large signal stability criterion of the AC-DC hybrid micro-grid system;The large signal stability criterion is limited to the amplitude processing based on the preset reference current limiting value, and the stability determination of the AC-DC hybrid micro-grid system is completed based on the large signal stability criterion containing current limiting amplitude.The reference current limiting value of the converter current inner loop is limited in the present disclosure, and the large signal stability criterion is optimized, so that the accuracy and practicability of stability criterion are further improved.

A kind of impedance model computer automatic construction method for multi-terminal flexible system.The method first obtains the steady state operating point of each element of system by power flow analysis, then establishes mathematical model for common elements of multi-terminal flexible system, and linearizes, discretizes based on steady state operating point, to establish element small signal state space model;Subsequently, the generalized incidence matrix group compatible with ac-dc hybrid system is used to realize element aggregation, obtain subsystem model and calculate its z domain impedance model, finally generate s domain impedance model by bilinear transformation.The invention realizes the computer-aided automatic construction of multi-terminal flexible system impedance model, supports the impedance fast analysis of any ac / dc port, is flexible and efficient;And the topological sensitivity of system is low, when the structure changes, only the corresponding part of generalized incidence matrix group needs to be modified, and the scalability is high.Example analysis shows that the invention can accurately obtain the ac / dc port impedance of multi-terminal flexible system, and effectively improve the analysis efficiency.

This invention discloses a wind turbine load reduction predictive control method and system based on mechanism and neural network models. The method includes the following steps: establishing a wind turbine mechanism analysis and neural network model; linearizing the wind turbine mechanism analysis and neural network model at the steady-state operating point of the wind turbine to construct a linearized model of the wind turbine; constructing a wind turbine load reduction predictive control model based on the linearized model, wherein the load reduction predictive control model aims to minimize the wind turbine load while balancing the wind turbine's power generation efficiency; and solving the load reduction predictive control model to obtain the optimal values ​​of various control parameters of the wind turbine. This invention can achieve a high-precision solution to the wind turbine load reduction control problem.