28 results about "Stability criterion" patented technology

This invention provides a method for reconstructing actuator faults in a heterogeneous multi-agent integrated energy system, relating to the field of fault diagnosis. The invention establishes a unified dynamic model for the agents; defines intermediate variables and constructs their dynamic equations; builds a global error dynamic system for distributed intermediate observers and agents; derives the stability criterion for the global error system based on Lyapunov stability theory, obtaining the state observer gain matrix for state estimation; loads the state observer gain matrix and the gain matrix for state estimation into each agent; and during the real-time operation of the agents, obtains the current state vector estimate and intermediate variable estimate, and calculates the reconstructed actuator fault value. This invention utilizes an output space coupling mechanism, enabling distributed collaboration between different energy networks without requiring a unified model dimension, thus breaking down the physical barriers to actuator fault reconstruction in integrated energy systems.

This invention discloses an active damping control method for bipolar DC distribution systems based on modulus decomposition. It incorporates line coupling into the system's stability criteria and active damping parameter design, deriving the pole-mode transformation matrix of the metal-return bipolar DC distribution system and obtaining a decoupling model of the bipolar DC line in the modulus component space. The modulus models of the source-side converter and load are also derived. Based on the established decoupling model of the bipolar DC distribution system in the modulus component space, an active damping control method based on modulus decomposition is proposed. This invention considers the impact of DC distribution lines on stability, incorporating line coupling into the system's stability criteria and active damping parameter design. The modulus damping control scheme proposed in this invention can more effectively suppress instability caused by the negative impedance characteristics of constant power loads and also provides a basis for parameter adjustment.

The present application belongs to the technical field of power system, and particularly relates to a time-delay power system stability analysis method and system. The method firstly establishes a load frequency control system model including time delay and nonlinear load disturbance, wherein the nonlinear load disturbance is a nonlinear disturbance taking unknown exogenous load disturbance as current and delayed state variable; then an augmented Lyapunov-Krasovskii functional is constructed, and an analysis method based on time-delay dependent matrix free matrix integral inequality and anti-convex combination inequality is adopted to analyze the stability of the load frequency control system, so as to obtain the stability criterion of the load frequency control system. The present application plays an important role in improving the calculation accuracy and time delay upper limit, and is helpful to expand the stable operation area of the power system.

This invention discloses an asymptotic stability control method for urban expressway convoys based on a distance-information adaptive criterion. Belonging to the field of intelligent convoy control technology, the method includes: collecting the relative distance and speed between the vehicle and the preceding vehicle, as well as the motion state information of multiple preceding vehicles; monitoring the communication link in real time and calculating the signal quality factor of each preceding vehicle; constructing a dual adaptive coupled car-following model, which adjusts the vehicle's acceleration through both distance sensitivity coefficients and information sensitivity coefficients; deriving the asymptotic stability criterion for the convoy in equilibrium state based on the dual adaptive coupled car-following model and calculating stability indices in real time; and executing a hierarchical closed-loop control strategy based on the stability indices. This invention can simultaneously utilize distance-based sensitivity adjustment to ensure short-range safety and dynamically adjust the coordination weights according to signal quality, ensuring the asymptotic stability of the convoy in high-speed flow and complex communication environments.

The application provides a vacuum mixing process optimization method and system, which comprises collecting mixing container cavity pressure, jacket temperature, material torque, stirring speed, and air extraction flow signal, calculating pressure change rate, torque fluctuation amplitude, air extraction amount per unit time, and pressure fluctuation characteristic quantity, dividing the vacuum mixing process into four stages of initial exhaust, bubble release, viscosity climb, and densification stability; in the initial exhaust section, the vacuum valve opening degree and time length are controlled according to the air extraction amount and the pressure change rate, and the pressure response delay is recorded; in the bubble release section, an air extraction and stop alternating sequence is generated, and the air extraction and stop time length is corrected in combination with the delay; in the viscosity climb section, the target pressure interval is determined according to the torque, temperature, and pressure change rate, and the speed and valve opening degree are cooperatively adjusted to stabilize the pressure; in the densification stability section, a stability criterion is constructed, and the valve opening degree is controlled as needed; when adjacent stages are switched, the target pressure starting point, valve opening degree initial value, speed initial value, and control period of the next stage are corrected according to the end parameters of the previous stage.

The application provides an inverter droop control method and system, electronic equipment and a readable storage medium. The method comprises: generating an initial curve family of reactive power and voltage on the inverter side based on an established single-machine infinite bus (SMIB) model; screening the generated initial curve family according to a preset power system static stability criterion to obtain a stable region atlas capable of meeting the stable operation of the SMIB model; setting various different droop control curves in the stable region atlas; and determining a droop coefficient range based on the intersection between the droop control curves and the stable region atlas, and performing reactive power-voltage droop control based on the droop coefficient range. The application can accurately identify the stable domain of the reactive power-voltage droop coefficient of the network type inverter in advance and offline by constructing the SMIB model and coupling the inherent mathematical relationship and strict stability criterion.

The embodiment of the application discloses a kind of simulation calculation methods, device, medium and equipment of thin shell transient jump behavior, method includes: establishing thin shell finite element analysis model;Thin shell transient jump behavior timing simulation analysis is carried out, in each time step It includes: calculating strain rate eigenvalue spectrum, obtaining the nonlinear strength index of each element and local stiffness spectrum radius;When the nonlinear criterion index of unit is greater than threshold value, while local stiffness spectrum radius is greater than threshold value, it is divided into explicit domain unit, using substep control technology, improve calculation precision, otherwise, it is divided into implicit domain unit;Using adaptive step length technology, large step length is advanced to improve calculation efficiency;Incremental potential energy function is calculated, using stability criterion, judge whether thin shell will enter deformation bifurcation point;Using the direction of the fastest direction of potential energy function drop to build deformation trial displacement vector, accurately capture the real physical path of jump behavior under various working conditions.

This invention discloses a method and related device for suppressing oscillations in parallel connection of grid-connected and grid-connected converters, belonging to the field of power grid control technology. The method includes: establishing a system model of a grid, grid-connected converters, and grid-connected converters in parallel connection according to the current grid connection scenario; constructing a sequence impedance model of the grid-connected converter based on the control model of the grid-connected converter; introducing a voltage outer loop bandwidth parameter and constructing a sequence impedance model of the grid-connected converter based on the control model of the grid-connected converter; calculating the equivalent aggregate impedance of the system at the grid connection point based on the sequence impedance models of the grid-connected and grid-connected converters, and establishing a stability criterion based on the real part of the equivalent aggregate impedance; and adjusting the impedance characteristics at the grid connection point by adjusting the voltage outer loop bandwidth parameter of the grid-connected converter according to the stability criterion, so that the positive resistance characteristic of the grid-connected converter cancels the negative damping of the grid-connected converter, thereby achieving oscillation suppression of the parallel connection of grid-connected and grid-connected converters.

This invention belongs to the field of underwater manipulator reliability analysis technology, and discloses a non-probabilistic reliability analysis method for underwater manipulators considering fluid-structure interaction effects. The method includes the following steps: quantifying the uncertainty of fluid load parameters under finite sample conditions using a non-probabilistic interval method; updating sample points based on Bayesian theory, and obtaining the relationship between interval parameters and reliability through analytical solutions; conducting strength and stability analysis of underwater manipulator components using the buckling stability criterion as the failure criterion to obtain the critical buckling load; performing uncertainty propagation analysis using the Taylor series expansion method to solve for the structural response interval corresponding to the non-probabilistic interval of the input uncertainty parameters; and comparing the response interval with the limit state equation using stress-strength interference theory or tolerance interference theory to establish a non-probabilistic Bayesian reliable reliability analysis model, suitable for reliability assessment of underwater manipulator components under small sample conditions.

This invention provides a control method for the operating conditions of a fuel cell system. The method includes: reading the upper limit of the vehicle's allowable power, system voltage constraints, and stability criteria; collecting the stack voltage, stack current, DC bus power, system voltage, and power demand to form an effective data set; calculating the allowable power amplitude of AC perturbation; applying a limited AC perturbation to the stack through a DC-DC converter module; collecting the stack voltage response and stack current response to obtain impedance characteristics and measurement reliability indicators; separating the bus power ripple component from the DC bus power; calculating the power ripple compensation amount and applying it after amplitude limiting to suppress power fluctuations caused by AC perturbation; determining the stack's water content state as flooded, normally water-content, membrane dry, or unreliable based on the invalid data collection marker, measurement reliability indicators, and impedance characteristics; and setting conservative control parameters in the unreliable state.

The application discloses a kind of stability detection method, device, equipment and medium of multi-conversion station system, it is related to power system technical field, method includes: obtaining the impedance matrix of multi-conversion station system;Obtain the port admittance matrix of converter in multi-conversion station system;According to impedance matrix and port admittance matrix, construct the return difference matrix of multi-conversion station system;Generalized radius coefficient of return difference matrix is defined;If generalized radius coefficient is less than preset threshold in research frequency band, then stability criterion is simplified based on generalized diagonal dominance, whether multi-conversion station system is stable according to the stability criterion after simplification is detected.The application constructs the return difference matrix of multi-conversion station system, and the coupling relationship between converter is quantified according to generalized radius coefficient of return difference matrix, if generalized radius coefficient is less than preset threshold, then it can be determined as weak coupling relationship, and then stability criterion is simplified based on generalized diagonal dominance, can reduce the complexity of detecting the stability of multi-conversion station system and improve detection efficiency.

The invention relates to the technical field of oil well development, and particularly discloses a method for evaluating the tripping-in performance of a long open hole section multifunctional integrated tubular column, and the method comprises the steps: collecting basic data of a target well; establishing a parallel computing model group based on the basic data; performing multi-dimensional risk analysis on the length of the open hole section, the buckling risk, the wellbore structure and the borehole curvature by utilizing the parallel computing model group to obtain a constraint relation combination; on the premise that the constraint relation combination is met, the long open hole section multifunctional integrated tubular column is verified according to three-level criteria, and the three-level criteria comprise a tripping-in dynamic criterion, a buckling stability criterion and a strength safety criterion; if the three-level criterion is met at the same time, outputting a judgment that safe tripping-in can be carried out; otherwise, outputting the judgment that the tripping risk exists. The method for evaluating the tripping-in performance of the long open hole section multifunctional integrated tubular column solves the problem that an existing evaluation method is difficult to deal with the multi-physics field coupling risk.

This invention discloses a distribution network voltage control method based on safety constraints and online hyperparameter optimization. The invention constructs a distribution network voltage state transition model under no-communication conditions; derives a stability criterion based on Banach's fixed-point theorem and solves for the stability safety constraints of the action gain of each controlled node; configures an independent reinforcement learning control agent for each controlled node and applies stability safety constraints and equipment capacity constraints; trains the agent using a group relative policy optimization algorithm, updating the policy network parameters based on the relative advantage value of the trajectory within the group; employs a hyperparameter optimization method based on a multi-armed slot machine to optimize the reinforcement learning training hyperparameters online; and achieves cross-scenario migration of the reinforcement learning control agent through parameter remapping and incremental training when the distribution network scenario changes. This invention can realize distribution network voltage control, reduce the risk of voltage instability, reduce the computational overhead of hyperparameter optimization, and achieve rapid cross-scenario migration and adaptation.

This invention discloses a stability assessment and control method for grid-connected converters during fault recovery based on the hybrid potential function theory. First, the grid-connected system parameters of the grid-connected converter are obtained, and its equivalent model in a synchronous rotating coordinate system is established. Second, the hybrid potential function of the system is constructed to extract the current potential and voltage potential. Then, an analytical stability criterion is derived as an evaluation index for quantifying the transient stability of the system. Finally, the peak value of transient overvoltage is substituted into the evaluation index to assess the system stability. Based on the evaluation index, the system parameters during fault recovery are adjusted to improve the system's stability margin, suppress voltage divergence and power oscillation at the moment of fault clearing, and ensure the converter's continuous synchronous support capability. This invention reveals the mechanism of transient overvoltage leading to the contraction of the system's stable domain at an analytical level, which can avoid the instability risk caused by overvoltage and provide a reliable quantitative basis for the safe operation of grid-connected converters.

This invention discloses a method and apparatus for analyzing low-frequency oscillations in a converter-synchronous machine hybrid power supply system, belonging to the field of power system transmission and distribution technology. The method includes: establishing a linearized model of the entire hybrid power supply system under small disturbances; establishing a port impedance model of the converter and an impedance model of the power network, as well as an external port impedance model of the synchronous machine considering the embedded internal impedance of the converter and a damping torque model of the synchronous machine; constructing a damping torque stability criterion based on the external port impedance matrix of the synchronous machine; analyzing the influence of the converter's dynamic characteristics on the phase shift of the main and auxiliary diagonal elements of the external port impedance model of the synchronous machine, and deriving the key factors inducing low-frequency oscillations in the converter-synchronous machine hybrid power supply system. This invention achieves a unified analysis framework independent of specific converter control strategies, effectively protecting the information privacy of both the power grid dispatching department and the converter operator, and providing guidance for suppressing low-frequency oscillations in converter-synchronous machine hybrid power supply systems.

The application provides a micro-grid hierarchical fractional order robust control method based on neural network order estimation, and belongs to the technical field of micro-grid control. The application establishes the mapping relationship between the micro-grid operation state parameters and the fractional order PID controller order parameters by constructing a neural network order estimator, adopts the fractional order PID controller which has better dynamic performance than the integer order PID, increases the adjustable integral order and differential order, and combines the self-optimization ability of the LSTM neural network, so that the fractional order PID controller can obtain more suitable parameter configuration under different working conditions. Meanwhile, the application establishes a small signal model of the micro-grid closed-loop system, constructs the stability criterion and the stability domain boundary based on the frequency domain analysis method, and checks and corrects the order parameters. The application significantly improves the adaptability of the system to complex working condition changes, improves the transient control performance of the micro-grid, reduces the overshoot and shortens the regulation time.

This invention discloses an adaptive preset-time bounded tracking control method under state constraints, belonging to the field of complex nonlinear system control technology. First, it proposes an actual preset-time bounded stability criterion, providing a theoretical basis for the artificial preset of the system convergence time. Second, it designs an adaptive actual preset-time bounded filter, achieving preset-time convergence of the filtering error while addressing the computational complexity explosion problem in backstepping control. Third, it maps the constrained system state to unconstrained variables through a state transformation function, naturally integrating state constraints into the controller design. Finally, it combines backstepping control and radial basis function neural networks to construct an adaptive preset-time bounded tracking controller. In this invention, all signals converge to a bounded range within a preset time, the system state always satisfies the preset constraints, and the tracking error reaches bounded stability within a preset time. This method is suitable for controlling high-order strict feedback nonlinear systems with state constraints.

A method for equivalent stability evaluation of new energy station, the method first equivalently regards the new energy station as an injected current source, establishes a multi-node network model containing synchronous generator, new energy station and infinite system; then, based on the node voltage equation, the system is simplified into an equivalent single-machine infinite system model through the elimination method, and the modified electromagnetic power expression of the synchronous generator after the new energy station is connected is derived; subsequently, the dynamic process of the active power of the new energy station recovering at a rate k after fault removal is analyzed, and its influence on the acceleration and deceleration areas in the swing of the power angle of the synchronous machine is analyzed; on this basis, a first swing and third swing transient power angle stability criterion is constructed with the recovery rate k as the variable; finally, the criterion is solved to obtain the safe allowable interval of the active power recovery rate k to ensure the transient stability of the system. The method provides an analysis tool for quantitatively evaluating the influence of new energy dynamics on the multi-swing stability of the system.

The invention discloses a micro-grid large signal stability analysis method for controlling a heterogeneous inverter, and relates to the technical field of stability analysis. Comprising the following steps: constructing a plurality of GFM inverter equivalent oscillator models and a plurality of GFL inverter equivalent oscillator models of the series-parallel island microgrid; all the equivalent vibrator models are simultaneously established, and an island series-parallel micro-grid network vibrator model is obtained; respectively determining a first stability domain between each GFM inverter and a paired GFM inverter connected with the GFM inverter, and a second stability domain between each GFM inverter and a paired GFL inverter connected with the GFM inverter; and traversing and crossing the first stability domain and the second stability domain of each GFM inverter to obtain the overall frequency stability domain of the system, and determining the large signal stability according to the overall frequency stability domain of the system. According to the method, the dimensionality and complexity of the stability criterion are reduced, and the criterion of the large signal stability of the micro-grid is easier to analyze and calculate.

This invention discloses a highway platoon asymptotic stability control system, method, and electronic equipment with a time-delay model, belonging to the field of vehicle-to-everything (V2X) and cooperative control technology for highways. It includes a data acquisition and calibration module, a platoon asymptotic stability criterion module, and a hierarchical control decision module. This invention improves the driving safety and traffic efficiency of highway platoons by collecting vehicle motion data in real time, calculating the stability index of each vehicle in the platoon, and triggering early warnings or control suggestions when approaching instability.

This invention provides a method and system for analyzing the safe operation of grid-connected offshore wind farms. The method includes: acquiring the network topology and operating parameters of the grid-connected offshore wind farm to construct a power flow feasible domain injection space and a node admittance matrix; obtaining the power flow feasible domain based on these two parameters to determine stability criteria; generating an operating sample set by determining the active power injection space of the grid-connected offshore wind system and the number of training samples; and combining the operating sample set and stability criteria to obtain a stability margin set, which is then used to train a margin prediction model under a nonlinear neural network for hyperparameter selection and early shutdown strategy training. Finally, the active power injection space of the grid-connected offshore wind system is used to obtain an operating condition set under the power flow feasible domain, and a stability margin prediction set is obtained under the margin prediction model to construct the low-frequency oscillation safety domain boundary of the grid-connected offshore wind system for safe operation analysis. This invention can improve the accuracy of safe operation analysis of grid-connected offshore wind farms.

This invention discloses an asymptotic stability control system, method, and electronic equipment for urban highway convoys based on a multi-time-delay model. Belonging to the field of vehicle-to-everything (V2X) and cooperative control technology for urban highways, the system includes a data acquisition and calibration module, a convoy asymptotic stability judgment module, and a system decision execution module. This invention innovatively establishes an asymptotic stability criterion including explicit time-delay terms, revealing the negative correlation mechanism between time delay and system damping. In terms of control strategy, a dynamic compensation mechanism based on the car-following resilience index is proposed. By collaboratively adjusting the car-following gain and V2X information weights, the safety and efficiency of the convoy are balanced during convoy travel, and the mechanism controls the gradual attenuation of disturbances propagating along the convoy. This invention relies on edge computing to achieve real-time response, combining single-vehicle intelligence and convoy cooperative optimization capabilities, thereby significantly improving the asymptotic stability, safety, and traffic efficiency of the convoy in complex urban environments.

The application discloses a behavior component fusion and stable takeover control method and system based on structure constraint, and relates to the fields of robot control, automation control and artificial intelligence control. The application acquires system state and calculates a risk index, triggers takeover when the risk exceeds a preset threshold and the system state continuously deteriorates, and switches to a fusion control mode. In the takeover state, a control output is generated through weighted combination of at least one pair of opposite behavior components, and the weight is continuously and dynamically adjusted based on the behavior conflict relationship instead of discrete switching. When the system state meets the stability criterion within a continuous number of control cycles, the takeover is automatically exited to restore the original control. The system is connected to the original system as an additional module, and the original controller does not need to be replaced, which can improve the stability of extreme states, avoid collision and maintain task continuity, and is suitable for various unmanned systems such as robots and automatic driving.

The application provides a micro-grid hierarchical fractional order robust control method based on neural network order estimation, and belongs to the technical field of micro-grid control. The application establishes the mapping relationship between the micro-grid operation state parameters and the fractional order PID controller order parameters by constructing a neural network order estimator, adopts the fractional order PID controller which has better dynamic performance than the integer order PID, increases the adjustable integral order and differential order, and combines the self-optimization ability of the LSTM neural network, so that the fractional order PID controller can obtain more suitable parameter configuration under different working conditions. Meanwhile, the application establishes a small signal model of the micro-grid closed-loop system, constructs the stability criterion and the stability domain boundary based on the frequency domain analysis method, and checks and corrects the order parameters. The application significantly improves the adaptability of the system to complex working condition changes, improves the transient control performance of the micro-grid, reduces the overshoot and shortens the regulation time.

This invention discloses a stability determination method and system for an automatic voltage control closed-loop system in a new energy base. The method includes: acquiring system parameters of the automatic voltage control closed-loop system; establishing a discrete state update model including the current cycle control command and the previous cycle control command; constructing augmented state variables and establishing a unified closed-loop discrete mapping relationship considering control laws and limiting constraints; dividing the state space into an unsaturated subspace and a saturated subspace according to whether the control command touches the limiting constraint, and establishing corresponding piecewise discrete mapping relationships; constructing a linear matrix inequality stability criterion for the unsaturated subspace under the condition that the voltage-reactive power characteristics satisfy the bounded incremental sector, and transforming it into a semi-positive definite programming problem to obtain the stability determination result. This invention can accurately characterize the dynamic behavior of the AVC closed loop in a new energy base under the combined effects of sample-and-hold, time delay, and limiting, and realize the analysis and determination of the system's stability state and oscillation mode.

This invention relates to the field of fluid control valve technology, specifically to a method and system for predicting the dynamic stability of a pilot-operated pressure reducing valve. The invention establishes a force balance equation containing p-Laplace terms and derives the stability criterion S for the pressure reducing valve to determine whether the valve system is stable. This allows for the assessment of whether parameter combinations will lead to oscillations during the design phase, avoiding trial and error and enabling the prediction of the pressure reducing valve's stability. The criterion is simple in form, can be calculated using a calculator or Excel, does not rely on complex simulations, and is highly concise. Furthermore, its p-value is adjustable, making it applicable to different media and operating conditions, thus offering wide applicability. This system can be embedded in an intelligent valve controller to achieve real-time stability warnings.

The application belongs to the technical field of new power system analysis, and discloses a multi-following network-structure network type converter system stability analysis method and an analysis system eq and Q ml ; joint diagonalization processing is performed on the matrices Q eq and Q ml , corresponding diagonal matrices Lambda eq and Lambda ml are obtained, n sets of characteristic parameters (lambda i , mu i ) are extracted, and it is judged whether (lambda i , mu i X RPC0 ) are all located above a critical stability curve of the following network type converter; if yes, the system is stable, otherwise, the system is unstable. Based on the above method, the stability criterion of the multi-following network-structure network type converter system can be simplified, the influence of the structure network type converter on the stability of the following network type equipment under different control modes can be determined, and thus the reactive power control strategy of the structure network type converter can be optimized, and the support capability of the structure network type converter on the power grid can be enhanced.

This invention relates to the design of a preset-time fault-tolerant control method for a two-dimensional heterogeneous intelligent connected vehicle (ICV) platoon. The invention constructs a preset-time fault-tolerant control method for a two-dimensional heterogeneous ICV platoon, including longitudinal / lateral two-dimensional dynamic models of the platoon under actuator failure and external interference, a fault-based two-dimensional dynamic coupling vehicle spacing error strategy, a distributed preset-time collaborative fault-tolerant control strategy for the platoon, and feasibility conditions and criteria. This invention addresses the heterogeneous ICV platoon system affected by actuator failure and external interference by constructing longitudinal and lateral two-dimensional dynamic models. Next, it combines multiple theories to build an information flow topology model and constructs a fault-based two-dimensional dynamic coupling vehicle spacing error strategy. Based on control theory, a distributed preset-time collaborative fault-tolerant control strategy is formed. Finally, an internal stability criterion is established to analyze and synthesize the platoon's stability, controllability, and observability. The beneficial effect of this invention is that it solves the preset-time fault-tolerant control problem of two-dimensional heterogeneous ICV platoons, improving the safety of ICV platoons.