52 results about "Steady state operating point" patented technology

The invention discloses an automatic load-variable multi-variable control method for an air separation device. According to the method, a module 1, namely a gain scheduling module, a module 2, namely a dynamic multi-variable model prediction control module, and a module 3, namely a process real-time optimization module are involved. The method comprises the following steps that: the module 3 calculates the optimal steady state value of a process variable related to load change according to the load-variable requirement of the device and sends the optimal steady state value to the module 2; the module 1 determines a prediction model adopted by a controller of the module 2 at the moment according to the current value of a scheduling variable; and the module 2 gradually pushes the device to the optimal steady state working point which is calculated by the module 3 on the premise of ensuring product quality and not going against equipment constraints. By the method, the problems of mutual decoupling of energy and a material, nonlinear control and the like in the wide-range load-variable process of the air separation device can be radically solved, smooth and quick transition among different working conditions is realized, and the load-variable operation quality and speed of the air separation device are ensured.

The invention relates to a method and system for monitoring a process based on slow feature analysis. The method comprises the steps of reading a slow feature model and a monitoring model, reading in an online measurement value of a process variable, forming an input vector, and inputting the input vector into the slow feature model to obtain an online real-time estimation value of a slow feature vector s(t); inputting a vector s1:M (t) formed by front M slow features into the monitoring model to obtain instant evaluation values of T<2> and S<2>; comparing T<2> with Ta<2> and S<2> with Sa<2>, judging that the process is shifted from a steady state operation point if T<2> is greater than or equal to Ta<2>, and judging that the process is subjected to dynamic feature variation if S<2> is greater than or equal to Sa<2>. According to the technical scheme, the shift of the steady state operation point can be monitored, and the dynamic feature variation of the process can be effectively monitored.

A system and method for controlling a digital pulse-width modulated power converter achieves a fast large-signal transient response while maintaining a slow response near the steady-state operating point in order to assure stability and to reduce the system's susceptibility to noise. Digital output error samples are processed through a gain scheduling block that applies a non-linear gain function to produce a weak loop response when the system is near its steady-state equilibrium point and a strong loop response when large transients are encountered. The resulting system maintains a fast transient response to large error signals while reducing noise and loop jittering and assuring loop stability.

A dynamic parameter identifying method for electric system non-invasive induction motor, including the steps as below: under no influences to the electric user, monitor and detect the electrical information of electric loads, if any induction motors put into operation, go to the next step, otherwise continue to monitor and detect; record the terminal voltage, and current data during the whole starting process of induction motor under any loads; fulfill the filtering of measured voltage, and current data, and the data smoothing; draw the pie chart of motor according to the smoothed data; and identify the parameters of induction motor according to the basic properties of motor pie chart and combined with the modern mathematic methods to optimize the parameters, and calculate the rotary speed of motor at the steady-state operating point according to the calculated parameters; calculate the deviation indexes of parameters; determine whether the deviation indexes meet with the specified standards, until all deviation indexes up to the relevant standards. The invention adopts the non-invasive parameter identification method, only through the current, and voltage information at the electrical inlet of loads, the service conditions and relevant dynamic parameters of user's induction motor may be obtained.

The invention relates to a method for analyzing small signal stability of an aircraft electric power system based on generalized state space averaging, comprising the steps as follows: establishing a power flow equation of the aircraft electric power system according to the structure of the aircraft electric power system, and determining the steady state working point of the aircraft electric power system; establishing an equivalent circuit for modeling the generalized state space averaging of the aircraft electric power system to obtain a nolinear differential equation of the aircraft electric power system; determining the state variable of the nolinear differential equation, and obtaining a generalized state space averaging model described by a fourier coefficient via Fourier decomposition; judging the small signal stability of the aircraft electric power system via calculating according to the model. The method of the invention realizes the analysis of small signal stability of the aircraft electric power system in different states, and realizes the sensitivity analysis of the small signal stability, which provides valuable suggestions for designing and improving the electric power system in large aircraft manufacturing process, and simultaneously provides reliable operation information of the aircraft electric power system for the flight crew.

By means of a pre-swirl device, in steady-state engine operation, the rotational speed lines of the compressor are moved, by increasing the swirl at the compressor inlet in the rotational direction of the compressor, to such an extent that the steady-state operating point of the compressor comes to rest approximately at the absorption limit of the compressor. In this way, the level of the charge pressure can be adjusted in a controlled fashion to the value required for the respective engine operating point. In the event of a sudden increase in the engine load, it is possible by resetting the pre-swirl grate to generate a charge pressure increase without a time-consuming rotor acceleration. The pre-swirl device therefore simultaneously assumes the functions of charge pressure and engine load control.

The invention discloses a realization method and system for a control outer ring of a solar array simulator. The method comprises steps of generating a UI-RI mixed data table based on a UI data table and a RI data table; and acquiring the sampling voltage of the output of the solar array simulator, searching the UI-RI mixed data table according to the sampling voltage, and obtaining the desired current of the corresponding working point on the I-V curve set by the solar array simulator The method of adopting the UI-RI mixed look-up table in the invention is advantageous for the operating point of the SAS on the whole set I-V curve, the linearity of the power current control is excellent, and the stable output can be maintained at any working point without being limited by the fill factor size of the set I-V curve. In the SAS load operating point fast step switch condition, quick convergence to the switched target operating point is realized, the dynamic response performance of SAS is greatly improved, and high dynamic response enables the spacecraft power system testing to be more reliable.

The invention discloses a distributed voltage-sharing control method for a modular ISOS combined system. The distributed voltage-sharing control method comprises the steps of: calculating a module input quantity, a reference signal and a system output quantity of each convertor module respectively and independently, so as to judge whether the convertor module deviates from a steady state operating point; and regulating the input power of one convertor module when an operating point of the convertor module deviates from the steady state operating point, so as to force the operating point of the convertor module to return to the steady state operating point, thereby realizing the voltage-sharing control. According to the distributed voltage-sharing control method for the modular ISOS combined system provided by the invention, the control circuits are distributed into the converter modules, so that the power circuits and control circuits of the converter modules are identical and can work independently, in addition, the voltage-sharing control of the converter modules is not related to that of the others in any way, thereby truly realizing the modular design of combined system, and being high in system redundancy, reliability and expandability.

The invention discloses a novel variable-step photovoltaic maximum power tracking system and method which are presented for the defects that a traditional maximum power tracking method cannot take both the dynamic property and the steady property into account and misjudgment is prone to occurring by taking a photovoltaic power generation system as a research object. The system is composed of a photovoltaic array, a boosted circuit, a DSP controller and a load, and the maximum power tracking method is a novel variable-step photovoltaic maximum power tracking control method based on a conductance increment method. Simulation verifies that when the outside light intensity acutely changes, the method can quickly and accurately track the system to change to quickly reach a new steady working point, and the better dynamic response characteristic is achieved; the important theoretical significance and practical value are achieved in the design of the photovoltaic power generation system.

The invention provides an automatic engine stable state calibration system. A parameter configuration module transmits configuration parameters to a monitoring and variable-locking module, the monitoring and variable-locking module calculates to lock parameters according to the configuration parameters, and transmits the parameters to a management module, the management module controls the operating state of an engine according to the locked parameters, a sensor acquires and feeds the operating parameters of the engine back to the monitoring and variable-locking module, the monitoring and variable-locking module judges the operating parameters and transmits the operating parameters meeting requirement to the parameter configuration module, and the parameter configuration module receives and processes the operating parameters meeting requirement and generates and outputs calibrated parameters; in addition, an automatic calibration method utilizes a personal computer (PC) to calculate the parameters of the engine, automatically try to configure the parameters of the engine, acquire the parameter information in the operation of the engine in real time and record the calibrated parameters reaching the stable operation point, an operator only needs to carry out simple configuration, and thereby a great deal of time and a lot of material resources are saved.

A power management method for a computer system is provided. The power management method includes: obtaining a system power consumption; determining whether the system power consumption is greater than a first safe operating point; when the system power consumption is greater than the first safe operating point, controlling a CPU and a graphics processing unit (GPU) to activate a frequency reduction mechanism according to a first adjustment sequence; when the system power consumption is not greater than the first safe operating point, determining whether the system power consumption is smaller than a second safe operating point; and when the system power consumption is smaller than the second safe operating point, controlling the CPU and the GPU to deactivate the frequency reduction mechanism according to a second adjustment sequence. The second adjustment sequence is reverse to the first adjustment sequence.

The invention relates to a method for calculating a droop coefficient of a flexible DC power grid converter station. The method comprises the steps of defining a generalized power sharing coefficient, selecting a preset common reference end, and using a DC voltage as a common voltage reference signal of a droop control station; expanding a steady-state working point of a VSCi-end active power balancing relation before DC network interference according to one-order Taylor's series, and writing a matrix form; calculating a linear analytic relation between a DC voltage change amount and a power step amount of a random converter station end in a system; calculating a least square problem of a generalized power sharing coefficient vector T for obtaining an optimal solution of the generalized power sharing coefficient vector T, and calculating the droop coefficient of each droop control station.

The present invention discloses a full-wave active rectification LLC resonant converter and a control policy thereof, belonging to the technical field of power electronic converters. The input source,an input bus capacitor, a primary side switching network, a resonance inductor, a resonance capacitor, a transformer, n (>=1) secondary side full-wave active rectification switching networks, m (>=0)secondary side full-wave rectification switching networks, an output filtering capacitor and an output load; when an input voltage is close to a rated working point, a secondary side assistant activeswitch tube maintains closure, and a convertor employs frequency conversion control; when an input voltage drops, the duty ratio of the secondary side assistant active switch is regulated to maintainthe stable output voltage; and the full-wave active rectification LLC resonant converter can meet two demands of the power system for the steady-state working point efficiency and the transient voltage drop, and is specially suitable for application occasions where the power system is required to have a power-down maintenance capacity such as a server power source and a rail traffic power source.

The invention discloses a stability analysis method of a single-phase voltage source based on the Jacobi theory. The method is characterized by, to begin with, establishing a mathematical model of a single-phase voltage source rectifier under a dq coordinate system; then, establishing a time domain nonlinear dynamic average model according to the mathematical model of the single-phase voltage source rectifier under the dq coordinate system; solving a steady-state operating point based on the mathematical model of the single-phase voltage source rectifier under the dq coordinate system; and finally, calculating the characteristic value of the system according to the Jacobi theory, and judging the stability of the system by utilizing a root locus method. The method adopts a time domain nonlinear model to make the system model clear and concise; and bullet train network side parameters and rectifier DC side parameters obtained based on the root locus method can affect the stability of thesystem.

The invention discloses an asymmetric cascade multi-level hybrid energy storage control method, and is suitable for phase splitting control of a single-phase cascade multi-level energy storage systemand a three-phase asymmetric cascade multi-level energy storage system. The method comprises the following steps of performing closed-loop control on a grid-connected current and a capacitor voltage,and determining an output voltage reference vector and a correction vector; determining a stable working range of the system according to the output voltage vector of the system, and by combining an inductor voltage, determining a steady-state working point; according to the steady-state working point, the output voltage reference vector and the correction vector, determining a battery link outputvoltage reference vector and a capacitor link output voltage reference vector; and determining a modulation wave according to the battery link output voltage reference vector and the capacitor link output voltage reference vector, generating a switch signal through SPWM, and driving an inverter to work. By virtue of the method, it can be guaranteed that the system can still operate stably in fourquadrants when a part of battery link breaks down, the control precision of the grid-connected current is improved, and the harmonic of the grid-connected current is reduced.

The invention provides a rotate speed recovery method, device and system for a double-fed wind power virtual synchronizer. The method comprises the following steps: collecting the rotate speed of a fan and judging whether the rotate speed of the fan reaches the lower limiting value or not; when the rotate speed of the fan reaches the lower limiting value, adjusting the output power of the fan to apower fixed value under the circumstance that the rotate speed of the fan is invariable, wherein the power fixed value is calculated from the wind speed when the rotate speed of the fan reaches the lower limiting value and the angular frequency of a wind wheel; keeping the output power invariable, and adjusting the rotate speed of the fan to a tracing rotate speed, wherein the tracing rotate speed is determined according to the power fixed value; and recovering the rotate speed of the fan to the rotate speed of the fan at the steady work point corresponding to the wind speed according to themaximum power point tracing curve.

The invention discloses a measuring and distinguishing method and system for an impedance model of an electric power system. The measuring and distinguishing method comprises the following steps thata port power frequency voltage and a port power frequency current are adjusted to set a stable-state working point, and a preset signal harmonic interference source is additionally arranged in an equipment port; the voltage and the current of the equipment port are collected, power frequency phasors and harmonic wave phasors of the voltage and the current are calculated through Fourier analysis; aworking condition row vector is calculated and obtained according to the power frequency voltage and current phasors, and an operating working condition is changed to obtain different coefficient rowvectors; a coefficient matrix is obtained according to the different coefficient row vectors and expanded, and a column vector is constructed; and equipment parameters are solved according to the expanded coefficient matrix and the column vector to obtain the impedance model of equipment. According to the measuring and distinguishing method, accurate calculation of the impedance model of the equipment under the situation that the operating working condition is changed constantly is effectively achieved, and the stability of the electric power system is effectively improved.

A method for dynamic fault simulation of a double-section type catalytic cracking reaction-regeneralion system comprises the steps that 1, a knowledge database is established, and a fault database is integrated; 2, based on DCS data and process model information of an industrial double-section type catalytic cracking device, a dynamic model of the double-section type catalytic cracking reaction-regeneralion system is established, and a dynamic model library of the double-section type catalytic cracking reaction-regeneralion system is established; 3, basic input data under different operating conditions is obtained according to the knowledge database, and steady-state working points for dynamic simulation are calculated; 4, specific fault types are selected from the fault database and converted into input deviations of the dynamic model, and dynamic fault simulation is performed; 5, an intelligent fault analysis module is applied to verify the fault types, simulation results are entered into the fault database to perfect the database. The system for dynamic fault simulation of the double-section type catalytic cracking reaction-regeneralion system comprises a DCS data acquisition module, the dynamic model of the double-section type catalytic cracking reaction-regeneralion system, the knowledge database, the knowledge database and the intelligent fault analysis module.

The embodiment of the invention discloses a power generation load steady state point extraction method and a device thereof, so as to solve the technical problem that extraction of a steady state load point from frequent-fluctuation historical data usually consumes large manpower and material resources and requires a unit to stop operating. The method of the embodiment of the invention comprises steps: S1, historical power generation load data are extracted from real-time operation data, and a power generation load data column vector D=[d1, d2,...,dN]<T> after equal-length sampling is recorded, wherein the N is the load data sample number; S2, the average value and the variance of the D and the bandwidth of a kernel density function determined by the variance are calculated; S3, the maximum value and the minimum value of the load data are found out, the load range is equally divided into preset parts, and the kernel density function is calculated; S4, the increment of the kernel density function is calculated; and S5, the symbol of the kernel density function increment is checked, and the load steady state point is determined.

The invention provides a control method of a high-order LCLCL direct-current converter. The method comprises the following steps: carrying out the circuit conversion of the high-order LCLCL direct-current converter, and obtaining an equivalent circuit and a corresponding nonlinear time-varying equation; introducing an extended description function into the nonlinear time-varying equation to obtain an extended description time-varying equation, and performing harmonic approximation to obtain a steady-state working point equation of the nonlinear time-varying equation; adding disturbance to the steady-state working point equation to obtain a small-signal steady-state working point equation; linearizing the small-signal steady-state working point equation to obtain a harmonic equation; and establishing a state space model by the harmonic equation, and further obtaining a small signal model. The compensator is designed for the small-signal model so as to realize compensation control of the converter.