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1430results about How to "Improve dynamic characteristics" patented technology

Model prediction control method of voltage source type rectifier when network voltage is unbalanced

The invention belongs to the field of power converter control and relates to a model prediction control method of a voltage source type rectifier when a network voltage is unbalanced. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced comprises the steps of converting three-phase network voltage and a three-phase current into network voltage and a current which are under a two-phase static coordinate system through an abc / alpha beta coordinate, obtaining network positive sequence voltage and negative sequence voltage by carrying positive and negative sequence component separation of the network voltage under the two-phase static coordinate system, calculating reference values of active power, calculating current reference values of the rectifier under the two-phase static coordinate system, and carrying out model prediction current control and selecting an optimal on-off state. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced is capable of quickly and precisely tracing the current under the two-phase static coordinate and effectively eliminating fluctuation of direct current side voltage at the same time, power quality of the system is improved, a reliable network-connected operation of the rectifier when transient state network voltage is unbalance is achieved, and dynamics and stability of the whole system are improved.
Owner:TIANJIN UNIV

Small high-speed five-axis linkage machine tool

The invention discloses a small high-speed five-axis linkage machine tool, which comprises a foundation structure, a spindle box component and a cradle type worktable. The spindle box component is supported on the foundation structure, and a crossbeam with a frame-shaped structure is arranged on two upright columns to form a bridge-type portal structure. The torque bearing capacity of the crossbeam is improved, the small high-speed five-axis linkage machine tool has all advantages of a five-axis linkage machine tool in the prior art, and carries identical machining reacting force, the volume of a structural part is reduced, and the weight of the structural part is greatly lightened; a spindle box is positioned between two transverse rods of the frame-shaped crossbeam, overturning moment is eliminated, and the stability of the machine tool can be guaranteed; in addition, sizes of various components are greatly reduced on the premise of identical machining capacity, and the stroke of the machine tool can be large in the design; and by the aid of the structure, the machining precision is greatly improved, the machining range is greatly expanded, better dynamic characteristics and higher feeding speed and higher cutting speed can be realized, cutting and machining time is greatly shortened, better surface machining quality is obtained, and machining efficiency is enhanced.
Owner:CHONGQING UNIV

Coupled four-freedom-degree parallel connection vibration isolation platform

A coupled four-freedom-degree parallel connection vibration isolation platform mainly comprises an upper platform, a lower platform, four main part branches and a middle constraint branch, wherein the four main part branches are identical in structure and used for connecting the upper platform and the lower platform. The tails of actuators of the main part branches are connected with the lower platform through universal joints, telescopic rods of the actuators are connected with the upper platform through ball joints, one end of a lower connecting rod in the middle constraint branch is connected with the lower platform through a universal joint, the other end of the lower connecting rod is connected with an upper connecting rod in a bell socket mode to form a sliding pair, namely the upper connecting rod can expand and retract in the lower connecting rod, the upper connecting rod of the sliding pair is sleeved with a spring, the other end of the upper connecting rod is connected with the upper platform through a rotating pair, and the axis of the rotating pair is parallel to one axis of the universal joint in the middle constraint branch. Lower hinge points of the four main part branches are symmetrically arranged in a square shape, upper hinge points are arranged in a trapezoid shape, and the trapezoid is symmetrical about the axis of a rotating pair of the middle constraint branch. The coupled four-freedom-degree parallel connection vibration isolation platform is simple in structure, large in bearing capacity and good in dynamic response characteristic.
Owner:YANSHAN UNIV

Coordination control method for double-fed asynchronous wind driven generator high voltage ride through

The invention discloses a coordination control method for double-fed asynchronous wind driven generator high voltage ride through, on the basis of a mathematical model of a double-fed asynchronous wind driven generator and gird side and rotor side converters of the double-fed asynchronous wind driven generator, allocation principles of active and reactive power of the grid side and rotor side converters of the double-fed wind driven generator are calculated, extremity expressions of active and reactive current are given, and a high voltage ride through implementation scheme capable of effectively providing dynamic reactive support for a power grid and eliminating direct current bus voltage, active power, reactive power and electromagnetic torque ripples is provided. The coordination control method in the invention can overcome defects of weak ride through capability and poor power grid stability of a wind driven generator in the prior art, thereby achieving the goal of optimal control of the generator when the power grid voltage is high; and the method can perfectly be implemented on the basis of original low voltage rid through hardware, thereby realizing joining with an existing low voltage ride through scheme of the unit, and forming a generalized voltage fault ride through control strategy capable of coping with a sudden change of amplitude of network voltage.
Owner:ZHEJIANG UNIV

Frequency conversion power source based on digital signal processor controlling

The invention relates to a variable-frequency power source based on the control of a digital signal processor, which comprises a switch power source module, a control circuit, a circuit for isolating and shaping pulse-width modulating signal, IPM inverting circuits, a circuit for detecting and protecting busbar voltage, a rectification input slow-start circuit, a communication circuit, an interface circuit for isolating and inputting parallel signals and an human-computer interface circuit for displaying the key. The invention adopts the structure of a single digital signal processor (DSP) coupled with the double IPM inverting circuits, provides two paths of independent variable-frequency power sources for two sets of asynchronous motors at the same time and carries out independent speed regulations to the two sets of asynchronous motors. The variable-frequency power source of the invention has the advantages of small volume, low power consumption, high reliability and being convenient for bulk production, etc., and adopts an appropriate switch frequency and an advanced voltage space vector pulse width modulation algorithm (SVPWM), thereby lowering the noise during the operation of the asynchronous motors and increasing the voltage utilization rate, with obvious effect on energy saving.
Owner:INST OF AUTOMATION CHINESE ACAD OF SCI

Integrated lead suspension for high density drive

The integrated lead suspension assembly comprises several improvements. An oversized terminating pad for the electrical traces and a smaller adjacent insulation layer on the flexure assembly enable laser solder ball bonding of the pads to the read/write terminal contacts on the slider without clamping operation. Consequently, the tip of the load beam can be made narrow for a structure that provides for head loading and unloading functions, which improves the dynamic performance of the suspension assembly. The flexure assembly is configured such that it requires no permanent bending in its forming process, and any permanent bending required is done to the load beam. The limiter that limits the travel of the flexure assembly is formed on the load beam and it is bent to the functional position only after attachment of the flexure assembly to the load beam. The limiter is configured and positioned at the leading edge side of the slider to optimize the unloading process and to minimize the possibility of disengagement of the limiter and the flexure assembly during high shock environment. Asymmetric backing branches are provided for the read and write traces in the flexure assembly located at the hinge area of the load beam, the widths of which are sized to optimize the dynamic signal performance of the read and write traces without impact on the vertical stiffness of the suspension. Low profile flanges at 30°–60° that bend from the plane of the load beam are provided along the edges of the load beam to optimize bending stiffness and flow induced vibration. Dimples are provided along the load beam to facilitate insertion of a plastic head separation tool.
Owner:WESTERN DIGITAL TECH INC

MEMS gyroscope robust self-adaptation control method based on neural network upper bound learning

InactiveCN104281056ACompensate for manufacturing errorsCompensate for interferenceAdaptive controlVibration amplitudeGyroscope
The invention discloses an MEMS gyroscope robust self-adaptation control method based on neural network upper bound learning. The method includes the following steps that an ideal kinetic model and an MEMS gyroscope kinetic model are established, a sliding mode function is designed, a control law is obtained based on the sliding mode function, and an RBF neural network upper bound estimated value is used as a gain of a robust item on the basis of the control law together with a feedback item and the robust item; a parameter self-adaptation law and a network weight self-adaptation law are designed based on a Lyapunov method. According to the MEMS gyroscope robust self-adaptation control method based on neural network upper bound learning, the feedback item is added in the control law, the two-shaft vibration trajectory tracking speed and the parameter estimation speed of an MEMS gyroscope are greatly increased, and the vibration amplitude is decreased; the robust item based on RBF neural network upper bound learning is added in the control law, the buffeting problem caused by large external disturbance and fluctuation and the problem that the dynamic characteristics are changed worse are solved, the uncertainty of a structural formula and the uncertainty of a non-structured formula are eliminated, and therefore the robustness of the system is further improved.
Owner:HOHAI UNIV CHANGZHOU

MDOF (multiple-degree-of-freedom) magnetic suspension motor

The invention provides an MDOF (multiple-degree-of-freedom) magnetic suspension motor, belonging to the technical field of motors. A magnetic suspension technology is combined with an MDOF motor technology to design the MDOF magnetic suspension motor. A spherical type MDOF magnetic suspension motor, a cylinder type MDOF magnetic suspension motor and a flat plate type MDOF magnetic suspension motor are provided, wherein a stator and a rotor of a rotating machine unit of the spherical type MDOF magnetic suspension motor are fixedly connected with a deflection motor unit and a suspension motor unit mainly by a primary structure and a secondary structure; a stator and a rotor of a rotating machine unit of the cylinder type MDOF magnetic suspension motor are fixedly connected with primary structures and secondary structures of an axial thrust and suspension motor unit respectively; and a primary structure and a secondary structure of a bilateral linear motor unit of the flat plate type MDOF magnetic suspension motor are fixedly connected with a primary structure and a secondary structure of an oriented suspension motor unit respectively. The MDOF control windings of the three motors are independent mutually and are not coupled; the same secondary structure is used for the suspension control and the deflection control, thereby being simple in structure; and the rotors are supported by adopting a magnetic suspension way, thus the friction does not occur, the speed is high and the service life is long.
Owner:HARBIN INST OF TECH

Ion beam figuring processing method for aspheric surface processing

The invention discloses an ion beam figuring processing method for aspheric surface processing, comprising the following steps of: firstly, detecting and testing to acquire a facial-contour error distribution data R and a removal function P; then, establishing an ion beam figuring processing path, and measuring and calculating incident angles phi of various points of an optical curved surface; calculating a resident time density function and a material removal amount M by using a calculation model and a resident time iterative algorithm, and calculating the resident times of ion beams in all processing points; carrying out linear triaxial-linkage numerical-control figuring processing on the optical surface of an optical element to be processed according to the established processing path and the resident time; then, carrying out facial-contour error detection, correcting the P according to the M and the facial-contour error distribution data before and after the processing, repeating the previous steps by using the corrected removal function P for iterative processing, and ending the processing till the requirement for facial-contour convergence precision is met. The processing method provided by the invention has the advantages of good stability, high processing precision, strong controllability and low requirement for equipment.
Owner:NAT UNIV OF DEFENSE TECH

Satellite mobile communication method fused with 5G network

The invention provides a satellite mobile communication method fused with a 5G network, and the method is characterized by comprising the following steps: carrying out the modeling of a satellite mobile communication scene, and carrying out the quantitative description of the system composition, a network structure, a communication link, a transmission system, and a working process; establishing high and low frequency networking; establishing satellite-ground cooperative cognitive wireless communication in a dynamic spectrum environment; performing high-dynamic compensation on Doppler frequency shift in mobile satellite communication; and realizing multi-user non-orthogonal multiple access in a mobile satellite communication environment. The method has the beneficial effects that the system effectively utilizes various spectrum resources to improve the data transmission rate and the system capacity; idle unlicensed spectrum is utilized by the system, and the problem of spectrum shortage is solved; the 5G air interface waveform is optimized to enable the 5G air interface waveform to adapt to high dynamic characteristics in a satellite communication scene; the spectrum utilization rate and the system capacity are effectively improved; the problems that a satellite mobile communication system is special in topology, difficult in routing and large in user service end-to-end time delay are effectively solved.
Owner:世讯航空技术有限公司

Monitoring method and optimal control method for supercritical circulating fluidized bed (CFB) boiler combustion signals

The invention discloses a monitoring method and an optimal control method for supercritical circulating fluidized bed (CFB) boiler combustion signals. The monitoring method comprises the following steps of: step 1, acquiring and pre-processing field data, and determining an auxiliary variable of an instant combustion carbon quantity model; step 2, building the instant combustion carbon quantity model based on mechanism modeling and data analysis hybrid modeling, and estimating the storage amount of instant combustion carbon in a hearth through a generalized Kalman filter information fusion technology, wherein the instant combustion carbon quantity model is shown in the description; and step 3, building a dynamic heat signal model, a hearth bed temperature signal model and a hearth outlet oxygen signal model through the instant combustion carbon quantity, and predetermining heat, bed temperatures and oxygen. The methods provided by the invention can accurately measure signals of heat, bed temperatures, oxygen and the like of a supercritical CFB boiler in real time, so that the optimal control on supercritical CFB boiler combustion is realized, and the combustion stability of the supercritical CFB boiler is improved.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode

The invention discloses a bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control method comprises steps of using a filtering capacitance voltage and inductive current as control variables to establish a mathematic model of a bidirectional direct-current converter, performing feedback linearization on an original state variable to form a new linearized state equation, tracking an error with a new state variable as an input of a controller, combining a back-stepping method with a sliding-mode variable structure and designing a feedback control rule of a converter system, wherein the feedback control rule of the inverter system is performed on pulse width modulation and controls the bidirectional direct-current converter. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode combines the feedback linearization with the back-stepping sliding mode control to apply to the bidirectional direct-current converter, solves a non-minimum phase characteristic and a variable structure characteristic of the converter, greatly reduces fluctuation of bus voltage, expands a stable area of a system and has a good engineering application prospect.
Owner:NANJING UNIV OF SCI & TECH

Piezoelectric sensor, beam type concrete sensor, and preparation methods and application thereof

The invention discloses a piezoelectric sensor. The piezoelectric sensor comprises an induction component, wherein the induction component comprises a piezoelectric material and a pair of electrodes positioned on the upper surface and the lower surface of the piezoelectric material; an encapsulated shell is wrapped outside the induction component; the pair of electrodes on the piezoelectric material are connected with each other through a screened lead running through the encapsulated shell; and the encapsulated shell is prepared by mixing epoxy resin, a curing agent and cement according to the mass ratio of the epoxy resin to the curing agent to the cement of 1:0.4:1. The invention also discloses a preparation method of the piezoelectric sensor, a beam type concrete sensor comprising the piezoelectric sensor and application thereof. The piezoelectric sensor is stable in signal, high in signal to noise ratio, small in road surface damage degree, high in durability, simple in preparation process and low in cost. The beam type concrete sensor is simple in preparation, adjustable in volume, high in sensitivity, high in response speed, insusceptible to damage during construction; and the calculated running speed of a vehicle is basically consistent with the actual running speed of the vehicle, the measuring result is accurate and the error is small.
Owner:UNIV OF JINAN

PIlambdaDmu controller parameter setting method based on parameter stability domain

The invention discloses a PIlambdaDmu controller parameter setting method based on a parameter stability domain. The method includes the following steps: judging if the input and the output of a controller system are stable, then determining parameter stability domain boundary curves at phase margin upper limit and at the position of phase margin appearing, determining a value range of two boundary curve frequency on the condition of ensuring parameters with practical significance, confirming the range of parameter Ki and Kp in the stability domain on the boundary curve, inserting a plurality of points on two boundary curves, determining a plurality of groups of points which are equal in Kp value respectively on the two boundary curves, obtaining a value range of Ki corresponding to the plurality of groups of points, determining an optimum value of Ki corresponding to each group of points by adopting a genetic algorithm, and finally determining an optimal solution through integral time absolute error (ITAE). According to the PIlambdaDmu controller parameter setting method based on the parameter stability domain, stable phase margin of a system and dynamic characteristics are both considered, and controller parameters are set by means of the genetic algorithm. A controller which is set by using the method can well control a system on the condition of meeting given stable phase margin, and therefore the fact that a system has better dynamic characteristics is guaranteed.
Owner:SHANGHAI JIAO TONG UNIV

Drum-type omni-directional turned mass damper

InactiveCN101672074AWith multi-dimensional shock absorptionEasy to makeShock proofingSteel ballOmni directional
The invention relates to a drum-type omni-directional turned mass damper, belonging to the technical field of vibration resistance and absorption in structural engineering, and comprising a top cover,an outer-wall sleeve connected with the top cover, a sleeve-type structure arranged inside the outer-wall sleeve, an internal horizontal baffle and an external horizontal baffle. The sleeve-type structure comprises an inner-ring core cylinder, an outer-ring core cylinder, a steel ball holder and a steel ball, wherein the inner-ring core cylinder is arranged in the outer-ring core cylinder, the outer surface of the inner-ring core cylinder is fixed with the steel ball holder that is internally equipped with the steel ball. A viscous damper is connected between the outer-ring core cylinder andthe outer-wall sleeve, the lower end faces of the inner-ring core cylinder and the outer-ring core cylinder are both connected with the internal horizontal baffle via a universal rolling spherical hinge, and a spring is connected between the internal horizontal baffle and the external horizontal baffle which is further fixedly connected with a substructure. The damper can be operable for turning energy consumption and vibration damping in all directions of the structure, namely, two horizontal directions, vertical direction, and two directions of reversing and swinging.
Owner:BEIJING UNIV OF TECH
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