309 results about "Differential coefficient" patented technology

Provided are an envelope processor 103, for obtaining an envelope for a detected signal; a FFT unit 104, for converting the envelope into a frequency spectrum; a peak detector 105, for smoothing the frequency spectrum by calculating a moving average, for further performing smoothing and differentiation for the spectrum, and detecting, as peaks, frequency points at which a sign of a differential coefficient is changed from positive to negative, for extracting peaks having a predetermined threshold value or greater, and for sorting the extracted peaks and detecting upper peaks; and a diagnosis processor T, for diagnosing an abnormality based on the detected peaks.

An abnormality diagnosis system for machinery comprises an envelope processing section (103) for determining the envelope of a detection signal, an FFT section (104) for converting the envelope into a frequency spectrum, a peak detecting unit (105) in which the frequency spectrum is smoothed by the moving average method, the resultant spectrum is subjected to a smoothed differentiation, frequency points at which the sign of differential coefficient changes from positive to negative are detected as peaks, peaks higher a predetermined threshold are extracted and sorted, and the higher ones are detected as peaks, and a diagnosis section (T) for performing abnormality diagnosis on the basis of the detected peaks.

The invention relates to a PMSM servo system control method based on fuzzy and active disturbance rejection control. A position signal is given by a differential tracker to arrange a transition process so that the contradiction between rapidness and overshoot of a system is solved, and uncertainty, friction torques and external disturbance due to modeling errors of the system are observed via an expansion state observer; according to the error between the differentials generated by the differential tracker and state variation generated by the expansion state observer, a fuzzy inference rule is obtained with application of experimental experience of technical staff, so that a fuzzy rule control table of an error proportion coefficient, a differential coefficient and an integration coefficient is established; accurate control amount is obtained after de-fuzzification, so that parameter self-adaptive adjustment of a nonlinear error feedback control law is realized; and compensation amounts of the nonlinear error feedback control law and the expansion state observer to the total disturbance forms the control amount, thereby realizing optimal control for an controlled object. The method of the invention improves both tracking precision and disturbance rejection capability of the system.

The invention provides a driving circuit and a driving method applied to a flyback-type converter and a quasi-resonant soft-switching flyback-type converter applying the same. According to a driving circuit applied to the flyback-type converter, differential coefficient of the drain-source voltage of a main power switch tube in the flyback-type converter is worked out by a differential circuit, thus leading the time when the drain-source voltage achieves valley floor to correspond to the time when the differential voltage passes the zero point in positive direction. A valley floor voltage detecting circuit is connected with the differential circuit and receives a differential voltage signal; when the drain-source voltage of the main power switch tube achieves the valley floor, a valley floor control signal is output, thus controlling the driving circuit to drive the main power switch tube, and further exactly realizing the aim of conducting the valley floor of the main power switch tube. By adopting the driving circuit, the aim of controlling a quasi-resonant soft switch of the main power switch tube is realized precisely, the driving circuit of the flyback-type converter is optimized so that the controlling effect and the reliability are greatly improved, and the realizing cost is reduced.

Provided are an envelope processor 103, for obtaining an envelope for a detected signal; a FFT unit 104, for converting the envelope into a frequency spectrum; a peak detector 105, for smoothing the frequency spectrum by calculating a moving average, for further performing smoothing and differentiation for the spectrum, and detecting, as peaks, frequency points at which a sign of a differential coefficient is changed from positive to negative, for extracting peaks having a predetermined threshold value or greater, and for sorting the extracted peaks and detecting upper peaks; and a diagnosis processor T, for diagnosing an abnormality based on the detected peaks.

The invention relates to a tail angle restraining guidance method based on sliding mode control, and belongs to the technical field of guidance. Firstly, a novel aircraft kinematics and dynamics model is built, then tail time is guided, distance between aircraft position coordinates and target position coordinates (xf, yf) is minimum, an expected tail end trajectory dip angle gamma f is a designed target, according to a back stepping method, a virtual control volume is designed to enable a sliding mode function and a differential coefficient to be simultaneously up to 0 in the tail time of flying, and according to Lyapunov method, trajectory dip angle change rate gamma' of an auxiliary control volume is obtained in a solving mode. The trajectory dip angle change rate is converted into an attack angle alpha, an aircraft novel model which is initially built is inputted, a track of the aircraft is adjusted in a real-time mode so as to meet an expected terminal condition, and therefore tail guidance is achieved. The method considers effect of aerodynamic characteristics of the aircraft on a guidance process, is more close to an actual condition, needs little information volume, and is wide in obtained trajectory dip angle tail value range, and smooth in obtained control volume change, and an attitude control system is easy to track.

The invention belongs to the field of application of photovoltaic power generating system control technology, and relates to a maximum power tracking control method for a monopole three-phase photovoltaic grid-connected system. The method comprises the following steps of: firstly, by testing voltage and current outputted by a photovoltaic array, working out a differential coefficient k of the output power to the voltage of the photovoltaic array and a change rate delta k of the k; secondly, according to the k and an output Step1 of a fuzzy controller (an input is k and delta k, and the output is Step1), jointly determining the disturbance step length and direction of a disturbance voltage delta U which is superposed on a reference voltage U ref of a maximum power point of the photovoltaic array, and making the U ref quickly iterative and then converged at the optimal reference voltage corresponding to the maximum power point of the photovoltaic array under the current environment; and finally, realizing the quick and accurate tracking of the output voltage of the photovoltaic array on the U ref by a double closed loop control system consisting of a voltage PI controller and a synchronous vector current PI controller with feedforward compensation.

The invention provides a voice noise reduction method for a conference terminal based on the neural network model. The method comprises steps that S1, an audio file is collected by the conference terminal device to generate a digital audio signal in the time domain; S2, the digital audio signal is framed, and short-time Fourier transform is performed; S3, the amplitude spectrum of the frequency domain is mapped into a frequency band, and a Mel-frequency cepstral coefficient is further solved; S4, first-order and second-order differential coefficients are calculated through utilizing the Mel-frequency cepstral coefficient, a pitch correlation coefficient is calculated on each frequency band, and pitch period features and VAD features are further extracted; S5, input characteristic parameters of an audio are used as the input of the neural network model, the neural network is trained offline, the frequency band gain generating the noise reduction speech is learned, and the trained weightis solidified; S6, the neural network model is utilized to learn, the frequency band gain is generated, the outputted frequency band gain is mapped to the spectrum, the phase information is added, and a noise reduction speech signal is reduced through inverse Fourier transform. The method is advantaged in that real-time noise reduction can be achieved.

A kind of AC spot welding dynamic resistance real time measure instrument and method in the welding technology field, the said instrument includes: the welding transformer, a couple of inverse parallel silicon control, Holtz current sensor, minitype Lowe's loop, net pressure synchronization loop, current zero cross pulse detection loop, the silicon control starting circuit, welding current signal conditioning circuit, current differential coefficient signal conditioning circuit, sound-light alarm circuit, clock and replacement circuit, periphery drive circuit, keyboard and display circuit, communication and interlocked interface circuit, DSP control system. The method is that: uses embedded artificial NN calculate the angle of welding dynamic power factor and the current flow, then calculate the silicon control whole flow current virtual value, calculate the dynamic resistance in the spot welding process by using the ratio of the dynamic power factor and the whole flow current virtual value. This invention can detect the angle of welding dynamic power factor in quarter cycle, the instrument is simple, the real-time ability is good, the measurement precision is high.

The invention relates to a method of controlling running of a modularized multi-level converter in a low frequency model, which belongs to the technical field of controlling multi-level power electronic converters. The method comprises the following steps: setting high frequency common mode voltage and high frequency ring current both required to be superimposed, revising a switching function of a submodule and bridge arm current, obtaining an expression of capacitance voltage differential coefficient of the submodule according to volt-ampere characteristics of capacitance of the submodule, and in order to allow the capacitance voltage of the submodule to only have high-frequency component, assuming high frequency common mode voltage is known to obtain a expression of the high frequency circular current; comparing a running frequency with a critical frequency to obtain frequency model selection signals, combining an energy control and a circular current control of a phase unit of the modularized multi-level converter, determining whether the high frequency common mode voltage and the high frequency circular current are required to be superimposed to an original instruction or not according to the frequency model selection signals, and generating voltage required to be superimposed in the bridge arm of the phase unit of the high frequency circular current by controlling. The method is easy to realize and strong in universality, and provides reference for low frequency application of the modularized multi-level converter.

This invention relates to a method for controlling charging of storage batteries with gas sensors, which tests oxygen content or gas pressure in the internal gas of the battery with a gas sensor or an outer pressure sensor then uses a differential coefficient method to compute the variety rate of the oxygen or gas pressure to decide its charge state to further determine a charging strategy, which is suitable for Ni-base watercourse batteries.

The invention provides a method and a system for self-adjusting fuzzy PID (Proportion Integration Differentiation) parameters in a furnace temperature control system. The method comprises the following steps: selecting and quantifying variables in a PID controller and finding out a fuzzy relation of three PID control parameters including a proportionality coefficient KP, an integral coefficient KI and a differential coefficient KD , and system deviation e and a deviation varying rate ec; establishing a fuzzy relation table; and carrying out online modification on the three parameters by a fuzzy control method. The system corresponds to the method. After PID parameter online fuzzy self-adjustment is carried out, a normal working state is automatically switched, and a PID parameter adjusting process is automatically started when system performances are changed and the readjusted PID parameters so that the system has the better control quality.

The invention discloses an ultra high-voltage alternating current transmission line protection method based on an all-component differential coefficient matrix, comprising the following steps that the fundamental frequency electric amount on both ends of an ultra high-voltage alternating current transmission line is measured; the positive, negative and zero sequence current amount on the other end is calculated from that on one end of the line with a long line equation; the fundamental frequency current amount on the other end is calculated through a symmetrical component method; and then a differential coefficient matrix is calculated. A fault type is judged according to the values of all elements of the differential coefficient matrix, and a fault phase is enabled to be correctly tripped. The method is applicable to protecting the whole fault process of the ultra high-voltage alternating current transmission line; and particularly when the ultra high-voltage alternating current transmission line has a single-phase high-resistance grounding short-circuit fault, the method can accurately identify and correctly trip the fault phase, and circuit breakers on both ends of other two normal phase lines are reliable without working.

The magnetic material for magnetic refrigeration of the present invention is characterized by exhibiting, in a certain temperature region, preferably, only in part of a temperature region from 200 K to 350 K, an inflection point at which a second order differential coefficient of a magnetization curve changes from positive to negative with respect to a magnetic field, within the range of this magnetic field formed using a permanent magnet unit. This magnetic material of the present invention can generate a low temperature by using a relatively low magnetic field, by transferring the entropy between the electron spin system and the lattice system near the temperature at which an inflection point appears on the magnetization curve. Examples of the magnetic material meeting this condition are La(Fe,Si)13, (Hf,Ta)Fe2, (Ti,Sc)Fe2, and (Nb,Mo)Fe2, each containing 50 to 60 atomic % of transition metals such as Fe.

A synchronizing apparatus, which controls, by a PLL circuit, a sampling clock to be used to sample input data and synchronizes a phase of the sampling clock with a target phase that is desirable for sampling the input data, includes: phase error detection means for detecting a phase error from sampling data and the sampling clock, the sampling data being sampled from the input data at timing of the sampling clock; frequency error detection means for detecting, based on a differential coefficient obtained as a result of detecting the phase error, a frequency error; and frequency correction means for correcting a frequency of the sampling clock such that the detected frequency error becomes close to zero by adding a frequency correction value to an integral term of a loop filter of the PLL circuit, the frequency correction value being calculated based on the frequency error.

The invention provides a quick digital image correlation measurement method based on stochastic parallel gradient descent optimization technology, comprising the following steps of comprehensively considering related parameters such as displacement, differential coefficient and the like of any one point in a speckle field of an object to be measured; and utilizing the stochastic parallel optimization technology to realize quick digital image correlation measurement. In the method, by adopting stochastic parallel disturbance on a deformation parameter, the correlation coefficient is convergentto a global unique extremum, thus obtaining the deformation parameter. The method has a simple principle, can be realized easily, is a DIC (digital image correlation) measurement method with totally new concept, can realize the aim of quickly measuring DIC with high precision and high reliability, and is expected to realize the real-time online measurement on the DIC.

The apparatus is designed for use in enhancing the complex texture details of digital image in real-time. It comprises a memory module, a phase-locking / shift circuit, a fractional order differential mask convolution circuit and a maximum value comparator. In the fractional order differential mask convolution circuit, the operation rules of 8 dedicated algorithm circuits use fractional order differential mask convolution scheme to achieve the spatial filter of digital image fractional order differential coefficient. The invention can be used in HDTV, biomedicine image, bank paper, satellite remote sensing, and creature characteristic graph.

The invention discloses an improved current loop control method for a photovoltaic grid-connected inverter, and belongs to the technical field of solar photovoltaic power generation. The method comprises the following steps that: a voltage feedforward control quantity u1 is obtained through commercial electricity voltage feedforward; 2, a current error [delta]i is obtained through a voltage outer loop control structure; 3, the current error [delta]i is segmented for forming a plurality of current error segments, each current error segment adopts different gains, and a current equivalent voltage duty ratio control quantity u2 is obtained after the current passes through a current inner loop control structure adopting a controller P; and 4, a command value u_order of a switch comparison register is obtained. The control method provided by the invention has the advantages that the realization is simple; complicated integral and differential coefficient setting is not needed; the introduction of virtual orthogonal signals is not needed; time-consuming dp coordinate transformation is avoided; meanwhile, the output current distortion can be effectively reduced; and the resistance capability on electricity grid distortion and harmonic interference is enhanced.

The invention provides a fuzzy control-based special PID (Proportion Integration Differentiation) method for controlling temperature of a plastic extrusion device. By taking the traditional PID control for reference and introducing an algorithm and an implementation mode of fuzzy rules, the method comprises a few important parts such as parameter fuzzification, fuzzy rule reasoning, parameter defuzzification, PID controller and the like. The method comprises the following steps of: calculating the deviation between an actual temperature and a theoretical temperature and current deviation variation speed according to reference input and feedback signals, performing fuzzy reasoning in a fuzzy reasoning device by means of fuzzy experience, performing fuzzification to convert an input value into a membership degree by means of a membership function of an input fuzzy set, outputting a proportion coefficient, an integration coefficient and a differentiation coefficient of a PID controller by the fuzzy reasoning device, and performing PID control by using the coefficients as references of the current controller. By calling the fuzzy rules of the heating and water cooling processes of a plastic extruder, nonlinear effect produced by water vaporizing and cooling in the cooling process can be effectively controlled, the temperature control of the whole main machine meets the requirement of the extrusion temperature, the extrusion quantity of the plastics is stabilized, and the product quality is improved.

The invention relates to a control method for inhibiting the influence on main steam pressure of a boiler caused by that a coal pulverizer is started or stopped, and a rapid control layer of average rotating speed of a coal feeder is added on the basis of three-layer control mode of the original boiler fuel, so that the influence on the main steam pressure of the boiler caused by various operation of the operators is effectively inhibited when in the process that the coal pulverizer is started or stopped. A dynamic feed-forward technique based on the actual differential coefficient is applied to the feed-forward design of a boiler main control system by the method, so that the command of automatically modifying the coal quantity in the boiler can be realized in the process that the coal pulverizer is started or stopped, and the excessive part of coal dust quantity which enters the boiler to be burnt is counteracted due to start grinding, warm grinding or stop grinding in the process of powder extraction, thus ensuring the combustion conditions of the boiler to be stabler and effectively inhibiting the influence on main steam pressure caused by that the coal pulverizer is started or stopped.

The invention discloses a current mutual inductor residual magnetism detection method based on small-signal gradient mapping. A differential coefficient of an initial operating point magnetic flow with respect to an exciting current is computed by exerting small voltage signals on a current mutual inductor for a second time, magnetizing curves of an iron core of the current mutual inductor are used for gradient mapping so as to confirm residual magnetism of the iron core of the current mutual inductor. According to the current mutual inductor residual magnetism detection method based on small-signal gradient mapping, the practical current mutual inductor is magnetized, so that current mutual inductance produces residual magnetism of different quantities. Effectiveness of the residual magnetism detection method and theory and practicability of a detection system platform are assessed, and the detection result indicates that the detection system platform is capable of quickly and accurately reflecting the quantity of residual magnetism of the iron core of the detected current mutual inductor.

It is a challenge to make it possible to produce a resonance suppression effect, and perform a stable control even in a case where a spring rigidity of a shaft significantly varies. The challenge is achieved as follows. In an engine bench system in which an engine 1 to be tested and a dynamometer 2 are coupled together by a coupling shaft 3, and a shaft torque control of the dynamometer is performed, a controller 5 includes: an integral element having an integral coefficient KI for a deviation (T12r−T12) between a shaft torque command T12r and a measured shaft torque T12; a differential element having a differential coefficient KD for the measured shaft torque T12; and a proportional element KP for the measured shaft torque T12. The controller 5 obtains a torque control signal T2 by subtracting the differential element and the proportional element from the integral element. Control parameters (KI, KP, KD, f1) are determined according to control characteristic parameters (a4, a3, a2, a1) set in a function calculation section 6, inertia moments J1, J2 of the engine and the dynamometer, and spring rigidity K12 of the coupling shaft.

The disclosed multivariable control method for distribution static reactive generator comprises: detecting the access-point voltage and dc-side capacitance voltage to compare with reference value and obtain error, calculating the error and error increment; taking the error and error increment as NN input to train NN and adjust PID controller parameters to obtain modulation parameter and phase difference for the inverter; obtaining the switch control signal. This invention is adaptive.

The invention relates to an FPGA-based maximum power tracking controller of a wind power system, comprising a sliding-mode extremum searching module and a fuzzy parameter setting module. Parameters ofthe sliding-mode extremum searching module are adjusted according to the output of the fuzzy parameter setting module; the sliding-mode extremum searching module comprises a comparison unit, a switching unit and two integrators; the fuzzy parameter setting module comprises a fuzzy controller; and power track errors and a wind speed are used as the input of the fuzzy controller. Small size, flexible design and high controller response speed of the controller are achieved because the maximum power tracking controller for searching a sliding-mode extremum of the wind power system is realized onan FPGA chip; parameters of a blower are unnecessary to know, and accurately measuring the wind speed and calculating the differential coefficient of the output power of the wind power system are notneeded, thereby high tracking precision and stability are achieved.

The invention discloses an ultra-high-voltage transmission line relay protection method based on a break variable differential coefficient matrix. The method includes by utilizing a distributed parameter model, computing three-phase current break variables of the other end of an ultra-high-voltage transmission line by positive, negative and zero-sequence voltage break variables and current break variables of one end of the ultra-high-voltage transmission line and positive, negative and zero-sequence current break variables of the other end of the ultra-high-voltage transmission line by the aid of a symmetrical component method, further computing the break variable differential coefficient matrix, forming protection criterions according to size relationships of elements of the break variable differential coefficient matrix, and distinguishing fault phases of the ultra-high-voltage transmission line. The distributed parameter model is used as a physical model and unaffected by distributed capacitance current, and the method is applicable to any voltage classes and in particular to ultra-high-voltage transmission lines.

The invention discloses an orbit expansion based multi-robot tracing formulation control method, comprising the following steps of: a) for a group of target orbit in a plane, expanding vectors of the target orbit, which point to each point on the orbit along the center of the target orbit, into an orbital cluster equivalent to an orbital function, and determining the movable range of robots; b) calculating tracing error by virtue of the orbital function, and designing the virtual angular velocity of the robots to ensure the tracing error to meet design requirements; c) calculating the generalized arc length and differential coefficient of the generalized arc length when the robots move along the orbit, by virtue of the orbital function and the target orbit, and designing the control force of the robots by virtue of neighbor information obtained by communication to realize formulation; d) calculating the error between the real angular velocity and the virtual angular velocity, and designing the control moment of force of the robot to complete tracing; and e) completing motion control on the robots by virtue of a servo system. The orbit expansion based multi-robot tracing formulation control method disclosed by the invention is especially applicable to nonholonomic constraint dynamic robots and simple and convexly- closed orbits. The method is simple and reliable, has higher accuracy and can be applied to multi-robot optimized information acquisition and the like.

The invention relates to a method for estimating the pseudo rate of a spacecraft based on attitude measurement information of star sensors and angular momentum measurement information of flywheels, solving the problem of low pseudo rate estimation accuracy in the prior art. The method is as follows: adopting the star sensors to measure the attitude of the spacecraft and obtaining the differential attitude angular velocity of the spacecraft after carrying out angle difference; collecting the angular momentum information of the flywheels and obtaining the differential coefficient of the pseudo rate of the spacecraft according to the obtained angular momentum information in combination with the attitude dynamics equation of the spacecraft; carrying out one-step prediction on the pseudo rate of the spacecraft; after setting the gain coefficient of the filter, using the differential attitude angular velocity as the measured value of the pseudo rate of the spacecraft and updating the filter of the pseudo rate of the spacecraft to obtain the estimation value of the pseudo rate of the spacecraft; and adjusting the gain coefficient value of the filter according to the estimation value, thereby adjusting the estimation value of the pseudo rate of the spacecraft and finishing estimation of the pseudo rate of the spacecraft. The method is suitable for the estimation occasions of the pseudo rate of the spacecraft.