50results about How to "Lower order" patented technology

The present invention relates to filter, coherent receiver device and coherent receiving method. The filter is used for converting a partial response signal into a full response signal, wherein the filter uses the following transfer function H_Pre-Filter(z) with respect to a partial response signal having a transfer function

in which A is other item, m and n are integers larger than or equal to 0 but not being 0 at the same time, 0<α<1.

The invention discloses a method for estimating city expressway traffic states based on mobile detection of smartphones, wherein a city expressway cell transmission model is built firstly, a observing network is built by adopting a smartphone to rapidly detect parameters, then a state space model based on a lighthill-whitham-richards (LWR) traffic flow model is designed, a traffic state and a boundary flux are synchronously estimated by utilizing three-step type recursive filters algorithm, then are coalesced with upstream and downstream subsection boundary flux by adopting a weighted average algorithm, and traffic parameter estimation is upgraded, thereby achieving real-time distributed estimation of city expressway network traffic state. The method for estimating the city expressway traffic states based on the mobile detection of the smartphones can collect average speed information of vehicles on any time and space positions of a loop, enables traffic estimation not to be restrained by the position of a detector, can achieve synchronization estimation of traffic density and boundary flux by designing a state-space model and a three-step recursive filter, and achieves the problem of large range expressway network traffic estimation by being coalesced with subsection boundary flux, reduces model order, and improves efficiency of algorithm.

The invention provides a d-q axis parameter identification method for a grid-connected inverter of a photovoltaic power generation system. The d-q axis parameter identification method includes: an inverter control reference value Udc-ref and Qref jump are arranged on the grid-connected inverter of the photovoltaic power generation system, or a three-phase short circuit fault is manufactured on the side of a power grid so as to collect disturbance data required by parameter identification; d axis parameters of the grid-connected converter are calculated according to the collected data, and the d axis parameters comprise filter inductance, d axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring active power control ring proportionality coefficients and outer ring active power control ring integral coefficients; and a filter inductance parameter is fixed to be a d axis identification result, q axis parameters of the grid-connected inverter are calculated according to the collected data, and the q axis parameters comprise q axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring reactive power control ring proportionality coefficients and outer ring active power control ring integral coefficients. The d-q axis parameter identification method for the grid-connected inverter of the photovoltaic power generation system reduces order and identification difficulty of a model to be recognized and improves identification accuracy.

The invention relates to a reactive power measurement method based on digital filter, which comprises: first, converting a couple of analog voltage and current signal into digital format; then, treating the signals with four digital phase-shift filters to obtain a couple of phase-shifted voltage signals and current signals; taking calculation and dc filter to the four signals to measure the reactive power data. This invention reduces request to digital phase-shift filter, and has small signal ripple in pure sine or with a little harmonic circuit as well as fast measurement speed.

Aiming at the problem of signal accumulation detection of a hypersonic velocity maneuvering target in a near space in a radar scanning period, the invention discloses a hypersonic velocity target TBD detection method for polynomial Hough conversion, and aims to search movement of a matching target in a radial dimension by using polynomial with velocity and acceleration as parameters, associate by using orientation wave gates in a direction, map the energy on a target track to a parameter space for polynomial Hough conversion, and detect by comparing the maximum energy value of the parameter space with a constant false alarm threshold. According to the method disclosed by the invention, the problem of two-dimensional parameter searching is degraded to the problems of one-dimensional distance search and small-range association in orientation by setting the orientation wave gates, the order times of polynomial search are reduced by setting range gates, and thus the calculation quantity is greatly reduced; meanwhile, in addition to functions of a conventional Hough conversion TBD method, the method disclosed by the invention is also applicable to signal accumulation detection under conditions of strong target movement, fuzzy distance measurement, multiple targets and the like.

The invention relates to a signal processing method of an angle measuring system of a photoelectric sensor. The angle measuring system comprises a high-frequency clock source, an ADC (analogue to digital converter) sampling pulse generator, a counter, an ADC circuit, a first counting number capturing circuit, a second counting number capturing circuit A6 and a digital processing unit, wherein the digital processing unit is used for reconstructing reference sine and cosine signals through a clock synchronizing reference signal recovery algorithm according to the inputted counting number and the counting number, recovering the reference sine wave and reference cosine wave which have the same phase with a pulse indication signal of the whole cycle, and completing phase sensitive demodulation on a detection signal obtained via ADC sampling by a minimum mean square error demodulation algorithm through the reference sine wave and reference cosine wave, so as to measure the angle of the photoelectric sensor. The signal processing method can be widely applied to the small-angle signal measuring of an electrostatic gyroscope, or be applied into the signal processing of the angle measuring system of the photoelectric sensor for the phase sensitive demodulation measuring using the pulse indication signal of the whole cycle as the reference signal.

Methods and apparatus for using WLAN chips, e.g., WiFi communications chips, to support communications in licensed frequency spectrum which is located outside unlicensed frequency spectrum available for unlicensed WiFi communications, are described. Through the use of low cost WiFi communications chips in frequency bands for which they were not originally intended, low cost communication is achieved in licensed frequency bands. Multimode devices are also possible in which communications may be implemented in either the licensed or unlicensed frequency band using a single WLAN transceiver chip.

The invention provides a method for carrying out composite predictive control on coagulant dosage of water treatment and relates to a method for controlling coagulant dosage of water treatment, and the method can be used for solving the problem of complex control over nonlinear uncertain objects during a coagulation process. The method comprises the following specific steps of: establishing a composite predictive control model; through detecting the turbidity of untreated water and the turbidity of effluent during the coagulation process of water treatment and combining an effluent quality set value, inputting the turbidity of untreated water, the turbidity of effluent and the effluent quality set value into the composite predictive control model so as to solve the real-time control quantity of coagulant dosage of water treatment, wherein in the establishment of the composite predictive control model, the coagulant dosage of water treatment in a water plant is controlled by utilizing composite predictive control method of simplified DMC (Dynamic Matrix Control) and untreated water quality disturbance feed-forward predictive control, and the turbidity of untreated water during feed-forward control can be predicted by utilizing a time sequence predication method based on AR (Auto Regression) predication. According to the invention, the control accuracy is improved by utilizing the combination of simplified DMC and feed-forward predictive control, and the problem that sampling usually has a certain time interval is solved by utilizing the time sequence predication method based on AR predication; and the method provided by the invention can be used for controlling the coagulant dosage of water treatment in the water plant.

The invention discloses a fluorescent microsphere co-doped with multiple near-infrared-II fluorescent dyes. The fluorescent microsphere comprises a macromolecule polymer microsphere and multiple near-infrared-II fluorescent dyes embedded in the macromolecule polymer microsphere. The invention also discloses a preparation method of the fluorescent microsphere. According to the invention, two or more near-infrared-II fluorescent dyes are embedded in a macromolecule polymer microsphere, and the ordered arrangement among molecules is reduced through different dye structures and mutual doping of molecular weights, so that the H aggregation and the J aggregation are further remarkably reduced, and the fluorescence intensity is enhanced so as to improve the detection sensitivity and the detectionaccuracy; and with the application of a fluorescent probe obtained by covalently coupling the fluorescent microsphere and a detection antibody in an immunodetection technology, the application prospect is wide.

The present invention discloses a three-phase full-bridge uninterruptible power supply control method with no need for a load current sensor. A three-phase uninterruptible power supply is widely applied to a distributed generation system, and is especially suitable for power supply of key loads such as the war industry, the medical treatment and advanced experiment devices, but the control methodmostly needs a load current sensor to ensure good robustness and control precision. An economical control strategy based on the Lyapunov large signal asymptotic stability principle is provided. Basedon the Lyapunov large signal asymptotic stability principle, an observer for real-time estimation of a load current and a corresponding control law are derived so as to omit three load current sensorsand greatly reduce the implementation cost. The zero steady-state error tracking control of a command voltage by the output voltage of the three-phase uninterruptible power supply is achieved, and good dynamic performances for various complex working conditions such as the resistance load jumping and non-linear load jumping are shown.

The invention relates to the modeling technology, and aims to provide a modeling method of a virtual synchronous generator taking an excitation circuit into consideration. Based on a three-phase bridge inverter topological structure, a power loop of the virtual synchronous generator is analyzed by neglecting an inner ring voltage and a current loop in a control system; by referring to a flux linkage equation, a voltage equation, a torque equation, a power equation and a motion equation of a traditional synchronous machine, a simplified motor model is proposed by further neglecting a derivativeterm and a zero sequence term in the model; in the model, the excitation current is calculated in a virtual mode by utilizing a reactive power deviation value and an excitation coefficient, and an excitation circuit is constructed; and the obtained motor model is expressed in a small signal disturbance mode, so that a low-order small signal model of the virtual synchronous generator taking the excitation circuit into consideration is obtained. According to the method, the grid-connected topological structure of the common inverter does not need to be changed, and a common grid-connected inverter which is mature and wide in application can be used for carrying out model research, so that the model test is completed under the condition that additional hardware cost is not increased.

The invention discloses a polynomial-trend-filtering-based OD matrix estimation method. A state variable is defined as a deviation of an actual OD flow relative to a historical value and the deviation is described as a random evolution process having a sliding trend; and then a polynomial trend filter model is established to realize estimation and prediction of a dynamic OD matrix. With the method, an optimal deviation-free estimation of a state can be obtained and a dynamic traffic flow evolution process can be described precisely.

The invention provides a wind turbine pitch variation execution mechanism robust control method based on H-infinity mixed sensitivity. The method comprises the following steps: establishing an open-loop transfer function GP (s) of a pitch variation execution mechanism; establishing a sensitivity function S and a complementary sensitivity function T; establishing weighting functions W1, W2, and W3 meeting constraint conditions; and establishing a closed-loop system transfer function Tzw (s) of a generalized controlled object of the pitch variation execution mechanism, and further obtaining a transfer function K(s) of an H-infinity controller Chinf. According to the method, the H-infinity mixed sensitivity robust control is applied to the wind power generation pitch variation execution mechanism, and an advanced control plan is provided for the pitch variation execution mechanism to carry out rapid and accurate pitch variation command tracking, thereby reducing tracking error, and improving tracking performance, dynamic performance, robust performance and anti-interference capability of the pitch variation execution mechanism.

The invention discloses a dynamic decoupling method and system for an accelerometer. The method includes the following steps that: the calibration-used data of the accelerometer are acquired, whereinthe calibration-used data contain input and output data at different frequencies under a condition that each axis is adopted as an input axis, and the other axes are respectively taken as output axes;a coupling function between the axes is fitted according to the input and output data; and a calibrated output result is finally obtained according to the coupling function. According to the method of the present invention, the coupling function is processed in a segmented manner, so that the order of the coupling function can be lowered, and therefore, the complexity of decoupling can be decreased, and the amount of calculation is lower; and the calibration data are adopted as the input data of a dynamic fitting formula, which enables high applicability; solving operation that needs large computation amount only lies in the obtaining of constant coefficients in the coupling formula, and in actual decoupling, only the formula needs to be directly invoked, and therefore, the computation burden of a processor can be effectively reduced.

The invention discloses a method for constructing a coordinate transformation matrix of a multiphase motor under an open-phase fault, comprising the following steps: (1) constructing a basic vector group M0; (2) constructing a first harmonic vector group HI; (3) constructing a first specific irrelevant group MI; (4) determining and processing the first specific irrelevant group MI; (5) constructing a third harmonic vector group HIII; (6) constructing a third specific irrelevant group MIII; (7) determining and processing the third specific irrelevant groups MIII; (8) according to the method inthe steps (5) to (7), constructing a fifth harmonic vector group HV and a fifth specific irrelevant group MVs, and determining and processing the fifth specific irrelevant group MV; (9) analogizing according to the step (8). The method is easy to realize, and can quickly and accurately obtain the coordinate transformation matrix of any multiphase motor under any open-phase fault. The obtained coordinate transformation matrix can reduce the dimensionality of the multiphase motor, simplify the original model of the multiphase motor, and can be used for multiphase motor fault modeling, fault characteristic signal extraction, fault tolerance control.

The invention discloses a magnetic suspension flexible rotor stability control method based on an optimal damping principle. The method comprises the following steps that firstly, a kinetic model of amagnetic levitation flexible rotor system is established through finite element analysis; unbalance response analysis is carried out on the model to obtain a transfer function of the flexible rotor system; the condition for a magnetic bearing control system to obtain the optimal damping at a first-order flexible mode is analyzed, and a phase compensation controller is designed to compensate the damping of the control system to the optimal value, thereby achieving the stability control of the flexible rotor system in the first-order flexible mode. Limited electromagnetic force of the magneticbearing can be fully utilized, and the method is particularly suitable for stability control over the magnetic suspension flexible rotor at the first-order critical rotating speed.

The invention provides a miniature gas turbine robust control method based on H(indefinite) mixed sensitivity, which comprises the following steps: according to a relationship between a micro-grid frequency deviation deltaf and a power deviation deltaP, establishing a transfer function Gp(s) of a miniature gas turbine; establishing a sensitivity function S and a complementary sensitivity function T, and constructing weighting functions W1, W2, W3 which satisfy restriction conditions; and establishing a closed-loop system transfer function Tzw(s) of a generalized controlled object of the micro-grid, and furthermore a transfer function K(s) of an H(indefinite) controller Chinf of the miniature gas turbine. According to the miniature gas turbine robust control method, an MT power controller based on robust H(indefinite) control is constructed, and defects of high difficulty for designing a plurality of controllers, low coordination, complicated structure, etc. in prior art can be overcome. Robustness, dynamic performance and interference resistance of a micro-grid system are effectively improved.

The invention discloses a digital fitting temperature compensation system of a resistance-type differential pressure transmitter, which relates to the field of sensor temperature compensation and correction, and is characterized by comprising a pressure transmitter, a digital pressure gauge, a digital power supply, a high-low temperature test box, a computer, an upper computer system, digital communication equipment and other auxiliary parts, and the digital pressure gauge, the digital power supply, the computer and the upper computer system are all connected with the high-low temperature experiment box. A temperature compensation method of a multivariable differential pressure transmitter for regional curved surface simulation is introduced, a model is subjected to segmented and interval curved surface simulation according to a test value and the function fitting precision of a single variable, and then temperature compensation and application of 0.2% FS and higher-precision products are achieved on the basis of collecting minimum data. High and low temperature tests are carried out for compensation, temperature excursion is small after compensation, and the compensation temperature range is not limited.

The invention provides a PID (Proportion Integration Differentiation) control method based on a stability coefficient multivariable strong coupling time-delay system, which comprises the following steps of: firstly, designing a compensator for the multivariable strong-coupling system in a frequency domain based on an RCGA (Remote Control Grid Array) to realize system decoupling, and processing the time-delay effect of each sub-loop by utilizing a Pade approximation method; then determining PID controller parameters for each sub-loop of the decoupled system on the basis of a stability coefficient, and finally applying the PID parameters of each sub-loop to a PID controller of an original multivariable system inserted into a compensator. The PID controller designed by the method can meet design requirements in multiple aspects of robust stability, output performance and the like; and meanwhile, the requirements of low order and easy realization can be met. The unknown parameters in the controller are solved through the given stability coefficient, so that understanding is facilitated, and the method has a high reference value for parameter determination of other system controllers. Simulation analysis proves that the designed system can give consideration to response characteristics and robustness at the same time, and the design process is simple and easy to implement.

The invention discloses a construction method of an SOC (state of charge)-OCV (open-circuit voltage) model of a lithium ion battery, which is used for improving the estimation accuracy capability of SOC of the lithium ion battery. The method mainly comprises steps as follows: 1) at the normal temperature, SOC and OCV data of the battery are actually measured; 2) the SOC is divided into three sections which are partially overlapped; 3) the three sections are subjected to low-order polynomial fitting; 4) the overlapped part is subjected to linear interpolation processing; 5) a fitting formula iscorrected with consideration of SOH change; 6) the fitting formula is corrected with consideration of temperature change; 7) the fitting formula is finally corrected with comprehensive considerationof SOH and temperature change; and 8) the SOC-OCV relation model is constructed. The method has the advantages as follows: the calculated quantity is small while the overall accuracy is high; a fitting model considers the influence of health degree of the battery on the model; the model complexity degree is not increased in a fitting result; the method has better universality and is not just limited to a certain battery; and the method has better adaptability and is suitable for conditions of environment change and battery feature decline after long-time application of the battery.

The embodiment of the invention discloses a total pressure sensor measurement error correction method and computer equipment. The correction method comprises the steps: acquiring a first correspondingrelation between a measurement error value of a total pressure sensor and a local attack angle of a pipe head position; acquiring a second corresponding relation between a real attack angle of an airplane and the local attack angle of the pipe head position; according to the first corresponding relationship and the second corresponding relationship, calculating a third corresponding relationshipbetween the real attack angle of the aircraft and the measurement error value; calculating a measurement error value of the total pressure sensor in the current flight state according to the third corresponding relation and the real attack angle, and calculating a total pressure compensation quantity value according to the calculated measurement error value; and calculating a total pressure correction value according to the total pressure compensation quantity value and a total pressure measurement value measured by the total pressure sensor. According to the embodiment of the invention, the total pressure measurement precision of the total pressure sensor under the condition of a large attack angle is improved, the atmospheric data indication accuracy is improved, and the safety of an airplane is improved.