117 results about "Equivalent system" patented technology

The present invention provides, e.g., apparatus comprising at least one processor; at least one memory including computer program code; the at least one memory and computer program code being configured, with at least one processor, to cause the apparatus at least to: respond to signaling containing information about an instant pressure and a flow rate of fluid being pumped in a pumping system, and obtain an adaptive control curve based at least partly on the instant pressure and flow rate using an adaptive moving average filter. The adaptive moving average filter may be based at least partly on a system flow equation: SAMAt=AMAF(Qt / √{square root over (ΔPt)}), where the function AMAF is an adaptive moving average filter (AMAF), and the parameters Q and ΔP are a system flow rate and differential pressure respectively. The at least one memory and computer program code may be configured to, with the at least one processor, to cause the apparatus at least to obtain an optimal control pressure set point from the adaptive control curve with respect to an instant flow rate or a moving average flow rate as SPt=MA(Qt) / SAMAt, where the function MA is a moving average filter (MA), to obtain a desired pump speed through a PID control.

The present invention provides, e.g., apparatus comprising at least one processor; at least one memory including computer program code; the at least one memory and computer program code being configured, with at least one processor, to cause the apparatus at least to: respond to signaling containing information about an instant pressure and a flow rate of fluid being pumped in a pumping system, and obtain an adaptive control curve based at least partly on the instant pressure and flow rate using an adaptive moving average filter. The adaptive moving average filter may be based at least partly on a system flow equation:SAMAt=AMAF(Qt / √{square root over (ΔPt)}),where the function AMAF is an adaptive moving average filter (AMAF), and the parameters Q and ΔP are a system flow rate and differential pressure respectively. The at least one memory and computer program code may be configured to, with the at least one processor, to cause the apparatus at least to obtain an optimal control pressure set point from the adaptive control curve with respect to an instant flow rate or a moving average flow rate asSPt=MA(Qt) / SAMAt,where the function MA is a moving average filter (MA), to obtain a desired pump speed through a PID control.

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The invention discloses a parameter adjusting method and system for improving the system efficiency of a rod-pumped well. The method comprises the steps that the downhole equivalent efficiency and the equivalent system efficiency are determined according to the ground efficiency of a pumping well system, the ground efficiency ideal value, the downhole efficiency of the pumping well system and the downhole efficiency ideal value, and an efficiency evaluation map of the pumping well system is established; the area is divided when the equivalent efficiency in the efficiency evaluation map of the pumping well system is smaller than the downhole equivalent efficiency according to the preset ground equivalent efficiency and the preset downhole equivalent efficiency; the active power, the polished rod loads, the stroke, the stroke frequency, the liquid production capacity of a single well pumping well, the dynamic liquid depth of the single well pumping well, wellhead oil pressure data and wellhead casting pressure data are collected to determine the downhole equivalent efficiency of a single well and the equivalent system efficiency of the single well, determine the area dividing positions of the single well in the evaluation map, and adjust the parameters of the pumping well system. The system efficiency level of different type pumping wells is evaluated fairly, and the method for improving the system efficiency of the pumping well is provided.

The invention discloses an operation method for safely applying a line protection device to a wind power station, which relates to the relay protection of a power plant and is provided aiming at solving the problem that the line protection device in the current system cannot meet the protective requirements of the wind power station very well. The operation method comprises the following steps of: firstly, establishing a real-time simulation model which is a virtual power grid environment, including fault points in a wind power station, a bus and transmission lines, a main transformer unit of a power generator, a current and voltage mutual inductor, an equivalent system and a simulation system; secondly; establishing an experimental detection platform including a real-time digital simulation work station, an RTDS (Real Time Digital System) real-time digital simulator, an analogue quantity output board card, a power amplifier, a line protection device, an analogue circuit breaker, a switch conversion device and a digital quantity input board card; and thirdly, accessing the line protection device to be detected to the power amplifier of the detection system, then connecting the line protection device with the analogue circuit breaker and carrying out various kinds of experiments. The experiment implemented by using the wind power station model and an onsite oscillograph of the wind power station can provide a real and accurate simulation environment so that validation possibility is improved, and therefore the line protection device to be detected can be safely used for the wind power station after detected.

The adaptive phasor measurement unit (PMU)-based series-compensated line (SCL) fault location method uses three different sets of pre-fault voltage and current phasor measurements at both terminals of the SCL. The three sets of local PMU measurements at each terminal are used for online calculation of a respective Thevenin Equivalent (TE). This enables representation of the power system pre-fault network with a reduced two-terminal equivalent system. The PMU measurements are also utilized for online calculation of the SCL parameters. This non-iterative method does not need knowledge of a time elapsed for the wave propagation from a fault point to a sending end and a receiving end. Two subroutines SA and SB are used for locating faults. A selection procedure is applied for indicating the valid subroutine and, hence, the actual fault location.

The invention discloses a method for performing electromagnetic transient-state simulation to a large power system. Firstly, equivalence is performed to an external system and specifically comprises the steps of sequentially obtaining sub-admittance rational functional expressions according to the sequence form an Mth sub external passive network to a first sub external passive network and finally obtaining a sub-admittance rational functional expression of the first sub external passive network to serve as a port admittance rational functional expression of the external system. An equivalent circuit of the external system is obtained through the port admittance rational functional expression of the external system. An external power supply is processed through the equivalent circuit of the external system to obtain an equivalent power source. After an equivalent system of an actual system is obtained, the electromagnetic transient-state simulation is performed to the equivalent system, harmonic waves and electromagnetic transient-state characteristics of a device and elements are detected through simulation results so as to judge whether the harmonic waves and transient-state components of the device, the elements and a local network are reasonable or not, if not, the electrical device is replaced, reasonable parameters are adjusted and corresponding measures are adopted, and if so, the process is finished.

The invention discloses an industrial robot joint rigidity modeling method which considers contact, and belongs to the field of industrial robot dynamic characteristic analysis study. By extracting key contact structure characteristics of each industrial robot joint, contact structures are assumed to be spring structures with a certain torsional rigidity, and an equivalent system model of all thejoints is built. According to measurement data, based on a power spectrum density method, three-dimensional surface fractal parameters and surface roughness parameters are calculated. All the contactstructures are subjected to stress analysis, and all contact pressure values corresponding to different joint input torques of the contact structures are calculated. By building an equivalent torsional rigidity model of springs in parallel connection and by making all contact rigidity and a reducer rigidity connected in parallel, a joint equivalent torsional rigidity is calculated. Through the combination of a fractal theory and structural stress analysis, an industrial robot joint rigidity model is built, by considering a contact rigidity, a more accurate theoretical estimation joint rigidityis calculated, and a certain method basis is provided for dynamic error compensation analysis at the tail end of the robot.

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.

Provided are a power system grouping and stability margin evaluation system and a power system grouping and stability margin evaluation method based on a wide area measurement system (WAMS). The power system grouping and stability margin evaluation system comprises a WAMS data platform, and a pretreatment unit and a transient analysis unit are sequentially connected at the back of the WAMS data platform. The WAMS data platform, the pretreatment unit and the transient analysis unit perform bi-directional transmission of information with a state quantity deposit unit. The method comprises: the WAMS data platform measures power-angle values of a machine set, the power-angle values are transmitted to the transient analysis unit after processed by the pretreatment unit, rotor angles of the machine set relative to local inertia center coordinates are calculated through the transient analysis unit and ranked from big to small, (n-1) angle clearances are calculated, the first three clearances are selected to serve as a leading mode at the moment, then an equivalent system trajectory corresponding to the leading mode is calculated, and finally a stability margin of the equivalent system trajectory is calculated. A network structure of a power system and models and parameters of elements do not need obtaining in advance, users do not need to install a WAMS device on each machine set, and grouping calculation can be performed quickly in real time after the system is disturbed or fails.

The invention relates to an assessment method of dynamic voltage recoverability of a sending end alternating-current and direct-current hybrid system after failing. The assessment method includes equating statically a practical system into an equivalent system, solving the dependency of the power angle of a system generator and an output power and the dependency of voltage and power angle, solving an acceleration area and a retardation area, and solving equivalent area stability margin (EASM) index. The higher the EASM index is, the higher the dynamic voltage recoverability of the sending end alternating-current and direct-current hybrid system after failing is. On the premise of not performing a time-domain simulation, the dynamic voltage recoverability of the sending end alternating-current and direct-current hybrid system after failing can be assessed with the assessment method, so that strength of the alternating-current and direct-current hybrid system is reflected. The EASM index can reflect affections of multiple factors on the voltage recoverability; and the multiple factors include generator inertia time constants, system short-circuit ratio, system initial working condition and the like. The problem that simulation precision has to be as precise as a generator inertial time constant in time-domain simulations is avoided.

A method for judging magnetic suspension rotor system stability, includes through establishing magnetic suspension rotor system radial rotational motion dynamics differential equation model, adopting plurality conversion converting real coefficient two variable equation to complex system monovariant form, to obtain monovariant equivalent system, then drawing open loop transfer function dual frequency Bode chart of equifinality complex system, utilizing generalized classic frequency field stability criteria judging rotor precession and nutation stability, providing require condition for designing raising system stability correction link. The present invention converts multivariable system to equifinality monovariant system, thereby capable of using classical monovariant control theory to proceed stability analysis, relative usual multivariable method such as state space analysis method etc, not only very visual but also having good robustness, thus more fitting real system application.

The invention discloses a novel composite control method based on a disturbance observer. The method can be used for suppressing mismatch disturbance in a voltage control type magnetic bearing system.The method is characterized by establishing a dynamic model of the voltage control type magnetic bearing system based on physical laws under mismatch disturbance; re-constructing an equivalent magnetic suspension rotor dynamic system by introducing a new state variable; and in the equivalent system, dividing mismatch disturbance into match and mismatch parts, wherein the match part is subjected to interference suppression through a robust controller, and the mismatch part is subjected to interference offset by designing a state space disturbance observer. The provided mismatch disturbance control method has important reference significance for high-precision suspension control of a magnetic bearing system.

The invention discloses an integrated navigation information fusion method based on interactive multiple models. The method comprises the steps that firstly, a GPS measurement subsystem is selected for algorithm measurement update; then a measurement vector of the measurement subsystem with the minimum fault detection value is selected to upgrade the interactive multiple models, a subsystem modelweight coefficient is calculated, the statistical characteristics of modeling noise of an equivalent system are calculated, and an equivalent system model is formed; measurement update of filter subsystems is carried out, and the state estimation of each filter subsystem is calculated; then a two-state propagation chi-square fault testing method is utilized to perform fault detection on the measurement subsystem and calculate the federated filter weight; combined with the state estimation and federated filter weight of each filter subsystem, the global state estimation and a corresponding estimation error covariance matrix are calculated; finally, global state estimation feedback is taken as an initial value for the next iteration. The integrated navigation information fusion method basedon the interactive multiple models can effectively select navigation measurement information, and reduces the navigation error generated by information fusion of multiple sensors.

The invention discloses an analysis method for multi-feed DC interaction factors based on reduced order Jacobian matrix, and the method comprises the steps as follows: simplifying and equivalently processing the DC- AC system to obtain the equivalent system; building the reduced order Jacobian matrix linearized model of the equivalent system; calculating multi-feed DC interaction factors through the related Jacobian matrix element. An analysis method for multi-feed DC interaction factors based on reduced order Jacobian matrix comprises the steps as follows: simplifying and equivalently processing the DC- AC system to obtain the equivalent system; building the reduced order Jacobian matrix linearized model of the equivalent system; calculating multi-feed DC interaction factors through the related Jacobian matrix element. MIIF can be calculated through Jacobian matrix related element, the existing running state of the system is not changed, the simulation experiment is avoided for calculating MIIF. The essence and impact factor for the MIIF are processed on theoretical derivation and analyzed, the former calculating method for MIIF is improved and the result is more reasonable and accurate.

The invention discloses a measuring method for equivalent system harmonic impedance of a feeder line in a power distribution network. The method comprises the following steps: 10) obtaining harmonic test data and forming a harmonic data group; 20) carrying out data pre-processing: carrying out data pre-processing on the harmonic test data obtained in the step 10) to obtain harmonic difference data; 30) screening the harmonic data: screening a sample data group through a Nair detection method based on the harmonic difference data obtained in the step 20); and 40) calculating the equivalent system harmonic impedance: according to the ratio of standardized coefficients in the sample data, deleting abnormal data in harmonic voltage difference data, and calculating the equivalent system harmonic impedance by utilizing the retained harmonic voltage difference data. The method is targeted for the feeder line in a substation, can accurately calculate the equivalent system harmonic impedance value of the test feeder line, and is helpful for carrying out quantitative analysis on harmonic pollution caused by the feeder line to the system.

The invention discloses a wind power farm grid-connected power transmission line instant single-phase grounding fault single-end distance measuring method. Three-phase voltages and three-phase currents at two specific moments are acquired on a wind farm side, and are used as inputs, and the three-phase voltages and the three-phase currents acquired on the wind farm side at two specific moments are used to calculate corresponding positive, negative, zero sequence voltage, current phasors. Based on a power transmission line distribution parameter model, the calculated wind farm side voltage, current sequence components are used to establish voltage, current relations on two ends of a power transmission line. Power supply potential, equivalent system impedance, fault distances and transition resistors of a system side are adopted as unknown quantities, and an established non-linear electric equation set is solved by using an improved Levenbery-Marquardt method, and an accurate fault distance measuring result is acquired. A problem of wind power farm grid-connected power transmission line fault distance measurement is effectively solved.

The invention relates to a multi-space aircraft attitude cooperation control method under input time delay. A multi-space aircraft distributed attitude cooperation control method based on a fuzzy theory is provided and input time delay existing in a controller is considered. A T-S fuzzy theory is used to construct a multi-aircraft attitude dynamics system into a fuzzy system composed of a series of fuzzy logics. A distributed controller is designed for the constructed fuzzy system, a closed-loop system is acquired, and equivalent conversion is performed in the closed-loop system. For the converted equivalent system, time delay depends on a Lyapunov stability theory so that sufficient conditions used for ensuring the stability of the system are given, and a linear matrix inequality method is used to design controller parameters. Compared with a traditional nonlinear compensation control method, the control method based on the fuzzy theory which is designed in the invention has a simplestructure, has high robustness for the input time delay, and has a less conservative property.

According to the present invention, there is provided a system and method for the collection, capture, processing, storage, and tracking of data for both electronic clinical trial and electronic source health records for purposes, based upon a single data collection instance. Upon the collection of data at a clinical trial site, the data are transmitted to a central server where it is captured as an electronic source document(s) in human readable format. The system then transmits the captured electronic source document to a trusted third-party's electronic document repository. Then, the system uses the same captured data to populate the clinical trial's electronic data capture database. The system incorporates security and encryption features to ensure that privacy information requirements are not violated. In the preferred embodiment, the electronic data capture provider for a clinical trial has no control over the server of the trusted third-party vendor, complying with regulatory requirements. Additionally, the collected data can be pushed into a clinical site's electronic health record system or any equivalent system which houses electronic data. Throughout the operation of the system, an audit trail is maintained which records information relating to all data recording, modifying, and accessing events.

The invention relates to the technical field of power system evaluation. The problem that a complete dynamic equivalent evaluation system is not established at present is solved. The invention provides a dynamic equivalent error evaluation method for a power system. Error analysis indexes of time series analysis are comprehensively and systematically introduced into effectiveness evaluation of dynamic equivalence. A finer and more accurate quantitative evaluation index system is provided and comprises a maximum error index, an average error index, a mean square error index or a root-mean-square error index, a correlation degree index and a posterior error inspection index, and an error evaluation system for confirming the effectiveness of the dynamic equivalent system is preliminarily established. Dynamic equivalence technology is advanced from an extensive experience stage to a refinement stage. The effective degree of the model can be recognized, so that a decision maker is helped toknow the reference share of the model when making a decision through the model, and meanwhile great help is provided for improving dynamic equivalence work, checking a dynamic equivalence method andthe like.

The invention provides an extended constrained polytope set-membership filtering method for a permanent magnet synchronous motor fault diagnosis model. The method comprises the steps of: constructinga nonlinear model equation of a control system of a permanent magnet synchronous motor; implementing a system state model by using a Taylor series to the model equation of the system to implement a linearized equivalent transformation, and using the constrained polytope to define system state variables to construct constrained polytope set operation rules; using dimension reduction and order reduction of the constrained polytope and scale multiplication rule to calculate the amount of system state variable error of the constrained polytope set; realizing an iterative calculation of a constrained polytope set-membership filtering and determining an estimated mean and an estimated variance matrix of the equivalent system state variables by a cross set calculation of the constrained polytope,and completing the iterative calculation. The extended constrained polytope set-membership filtering method has better algorithm effectiveness and computational efficiency, and it can be applied to the fault diagnosis problem of the permanent magnet synchronous motor control system, and realizes the optimal filtering calculation of the model state parameter of the permanent magnet synchronous motor control system.

The invention discloses a classification optimization method used for equivalent model parameters of electrical power system and based on trace sensitivity. Firstly, electrical power systems considering load dynamics are divided into groups and gathered, and a system dynamic equivalent model structure and a parameter initial value are determined; dynamic responses of an original system and an equivalent system are calculated under a presupposed fault with an implicit trapezoidal integration method; trace sensitivity of active power, reactive power and boundary node voltage of all call wires to an equivalent model parameter are calculated according to a jacobian matrix output in a calculation process; the trace sensitivity is subjected to normalization processing, average values of the sensitivity are sorted by size, and a static parameter and a dynamic parameter are divided; the static parameter is subjected to least squares optimization according to a steady state time interval response curve and the trace sensitivity, and then a dynamic response time interval response curve is subjected to predicting correction according to the static parameter correction quantity and the trace sensitivity, and the dynamic parameter is optimized; and an equivalent model optimal parameter which meets the requirement of the accuracy can be obtained after a little optimization iteration.

The invention discloses an adaptive reclosing judgment method for a single-phase grounding fault of a power transmission line, and the method comprises the steps: collecting three-phase voltages and three-phase currents of one side of the power transmission line at two moments, and enabling the three-phase voltages and three-phase currents to serve as input; calculating the corresponding positive and negative zero-sequence voltage and current phasors through employing the measured voltages and currents at the two moments; Building equations for two types of possible faults (perpetual single-phase grounding fault and instantaneous single-phase grounding fault) based on a power transmission line distribution parameter model, and describing the relation of voltages and currents of two sides of the power transmission line, and obtaining two systems of nonlinear equations; taking the power potential, equivalent system impedance, fault distance and transition resistance of a measurement point opposite side system as unknown quantities, solving the built systems of nonlinear equations, respectively obtaining fault range finding results of the two systems of nonlinear equations, solving the ratio of the fault range finding results, determining that the perpetual single-phase grounding fault happens if the ratio is less than a threshold value, and locking the reclosing function, or else determining that the instantaneous single-phase grounding fault happens, and carrying out the reclosing.

The invention discloses a multilevel elicitation method dynamic planning based power system dynamic equivalent method, and relates to the technical field of stability analysis for a power system. According to the method, dynamic characteristics of an original complex system can be tracked by a simplified system under variable working conditions so as to accelerate the safety and stability analysis process for the power system. A homology equivalent method is adopted firstly to perform dynamic equivalence on the original system; then a multilevel elicitation method dynamic planning algorithm dynamic link is introduced into an equivalent system; the link is subjected to off-line training so as to obtain the equivalent system containing the multilevel elicitation method dynamic planning algorithm; according to the equivalent system, tracking for the dynamic characteristics of the original system can be realized under the variable working conditions, so that the equivalent system is relatively high in adaptability; the power system dynamic equivalent method has the advantages that the shortcoming of low adaptability of the existing equivalent method is overcome, the equivalent precision is greatly improved, and the effectiveness for transient stability analysis for the power system is ensured.

The invention discloses a distributed resource distribution method for a multiple input multiple output (MIMO)-orthogonal frequency division multiple access (OFDMA) wireless relay system. The method comprises the following steps of: (1) initializing parameters of the MIMO-OFDMA wireless relay system; (2) sequentially calculating values of user terminals within a charge range of a relay node according to channel state information and lagrangian multipliers set by a base station, and sending calculation results of sub-carrier distribution values, equivalent system power distribution values and time delay sensitive user throughput capacity to the base station; (3) feeding back a new lagrangian multiplier result to the relay node through the base station; and (4) judging whether the sub-carrier distribution values and the power distribution values are converged or not by the relay node, and finally obtaining a final resource distribution result. According to the method, based on a multi-user and multi-carrier-system dual optimization theory and weights of multiple users, power and sub-carrier sources can be rational distributed by a rate adaptive distributed algorithm; and the calculation amount of the base station can be effectively reduced.

The split signal received in the channel is transferred to two sub decoders. With the channel receiving signal being received, the subdecoder 1 calculates out the external information and the information bits size of the equivalent system by using the module in soft-in and sort-out. The sub decoder 2 receives the said information from the output of the decoder 1. Then, the sub decoder 2 calculates and outputs the external information, transferring the information to the decoder 1. Thus, one time of iteration is completed. When the number of iteration reaches a preset value, with the interlacement of the external information output from the decoder 2 being removed, the hard decision is carried out to obtain a estimate value for each information bit, and the decoding procedure is completed.The invention features simple, practical and easy to implement in digital format, suitable to wireless and satellite communications area.

The invention relates to the field of optical amplification, and provides an optical amplification module of a folding optical path. The optical amplification module of a folding optical path comprises an imaging lens, a phase retarder and a circularly polarized transflective selector, wherein the imaging lens, the phase retarder and the circularly polarized transflective selector arranged in theoptical path successively; linearly polarized optical images pass the three devices successively; when the phase retarder performs polarization conversion on the passed optical images and the circularly polarized transflective selector performs transflective selection on the circularly polarized light, the optical images pass the imaging lens for two times so as to be amplified; and the actual system length of the optical amplification module is less than the equivalent system length, and the system can realize optical amplification in a short distance condition by using only the three devices. Therefore, the optical amplification module of a folding optical path has the advantages of being low in regulating difficulty, being low in complexity of the optical path, and having no excessive nondeterminacy.

The present invention provides a method which is used for calculating Thevenin equivalent parameters of power system. The active power and reactive power of a tidal current equation are respectively used for differentiating the Thevenin equivalent parameters so as to form a total differential equation system; the total differential equation system is solved with the Thevenin equivalent parameters as variables, so as to acquire the Thevenin equivalent parameters. The method overcomes the serious error in the existing calculating which assumes the invariable Thevenin equivalent parameters between two time steps, has the characteristics of strong adaptability, simple use and small amount of calculation, and can be used for analysis, calculation and on-site installation of the power system which requires a Thevenin equivalent system.