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2615 results about "System stability" patented technology

System Stability. The system stability is “the finite output produced by a finite input of the system”. If the output of the system is infinite even when a finite input applied to a system, then this system is called “unstable system”, that is, stable system has bounded output when bounded input is applied to a system.

Method for islanding microgrid control and optimization based on rotating coordinate virtual impedance

The invention discloses a method for islanding microgrid control and optimization based on rotating coordinate virtual impedance. Aiming to a fact that the actual microgrids have complicated impedance characteristics, the method for islanding microgrid control and optimization based on the rotating coordinate virtual impedance includes utilizing the coordinate rotation orthogonal transformation to design the coordinate rotation virtual impedance, improving the impedance characteristics of the microgrid, compensating errors of power distribution and improving power decoupling performance; establishing a complete small-signal dynamic model of the microgrid, wherein the small-signal dynamic model comprises distributed energy sources, power converters, loads and power grids, and guiding the selection of an optimal value on the basis of the small-signal dynamic analytical method; and simultaneously, providing a theoretical basis for the optimization selection of islanding microgrid control parameters by using the small-signal dynamic analytical method, wherein the islanding microgrid control parameters comprise droop control coefficients of the power distribution, process identifier (PI) parameters of a voltage current feedback controller, feedforward control coefficients and the like. The microgrid after being subjected to optimization design in an islanded operational mode is capable of effectively achieving power decoupling and improving the accuracy of the power distribution, the stability of the system and the dynamic performances.
Owner:SHANDONG UNIV

Spacecraft attitude integral sliding mode fault tolerance control method taking consideration of performer fault

The invention relates to a spacecraft attitude integral sliding mode fault tolerance control method taking consideration of a performer fault and provides a robustness attitude active fault tolerance control method based on an integral sliding mode surface for problems of the performer fault, external disturbance and control moment amplitude limits in a spacecraft attitude control process. The method comprises steps that firstly, a spacecraft attitude dynamics model taking consideration of the performer fault and containing external disturbance is established; secondly, on the condition that a performer is not in fault, a designed nominal controller can guarantee system stability, and input saturation amplitude limits can be easily satisfied through adjusting controller parameters; lastly, the fault information is introduced to design an integral sliding mode controller, robustness of external disturbance and the performer fault can be effectively improved, system stability is analyzed on the basis of an Lyapunov method. The method is advantaged in that stability of the attitude control system is guaranteed when a spacecraft operating on orbit generates the performer fault, and relatively strong fault tolerance capability and external disturbance robustness are realized.
Owner:BEIHANG UNIV

Variable air volume air-conditioner control system with variable frequency fan and digital air valve for adjusting tail end air volume and implementation method

The invention discloses a variable air volume air-conditioner control system with a variable frequency fan and a digital air valve for adjusting tail end air volume and an implementation method, belonging to the technical field of the control of a variable air volume air-conditioner system. The variable air volume air-conditioner control system structurally comprises a master station DDC (direct digital control) controller, a tail end temperature controller, a filed bus, a tail end variable air volume box (VAV-BOX) and an air valve driver, comprises mater station DDC control and tail end temperature controller control in control types, and adopts a strategy of collective processing at first and decentralized control later. Through a method for adjusting the tail end air volume by the variable frequency fan and the digital air valve, the variable air volume air-conditioner system eliminates throttle energy loss of the air valve without a device for measuring the air volume, has simple control type and no influence on the operation of the whole variable air volume system, and has the advantages of good system stability and obvious energy-saving effect; and the fault on the variable air volume tail end device of certain node has no influence on the normal operation of other variable air volume tail end devices.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS +1

Enhanced data right protection method based on block chain and smart contract

InactiveCN107507091ACannot be deletedCan not be modifiedFinanceDigital data authenticationData PropertySystem stability
The present invention belongs to the data safety technology field, especially to an enhanced data right protection method based on a block chain and a smart contract. The method comprises the steps: a data owner submits data attributes and strategy attributes to a smart contract at a block chain for data publishing; other users are taken as data assignees to allow the circulation attributes of the data assignee to take as parameters to call the smart contract to perform circulation application, after the smart contract automatically determines whether the application is valid or not according to the strategy attributes of the data, an application result is returned back; if the circulation attributes of the data assignees are valid, a circulation license authorized and generated by the smart contract is obtained; or else, the smart contract determines that the application is failed. The enhanced data right protection method based on the block chain and the smart contract applies the block chain technology to protect data owner right and justly accept the applications of each data assignee; and moreover, the enhanced data right protection method based on the block chain and the smart contract improves the system stability, remove the dependence on a third-party authority in the data right protection process and provide a just, transparent and trusted execution environment for the data circulation process.
Owner:FUDAN UNIV

Efficient direct-expansion solar heat pump and water source heat pump coupled heat supplying system

The invention discloses an efficient direct-expansion solar heat pump and water source heat pump coupled heat supplying system. The system is characterized in that the angle of a solar heat collector is adjusted in real time through a full-automatic solar tracking device, therefore, sunlight vertically irradiates the solar heat collector, and maximum solar radiation energy is achieved; by arranging a phase change heat storage device on a direct-expansion solar heat pump system, the evaporating temperature of a refrigerating agent is kept within a certain range, and then influences of changes of the solar radiation intensity to the system stability are greatly reduced; solar energy is stored through a heat storage water tank, intermediate water is preheated through the heat storage water tank, therefore, heat obtained through the direct-expansion solar heat pump system is effectively transmitted to a user, and then effective coupling of a solar heat collection and heat storage technology and a water source heat pump is completed. The efficient direct-expansion solar heat pump and water source heat pump coupled heat supplying system has the advantages that the problems of intermittency and unstability of solar energy sources are effectively solved, it is guaranteed that the system can stably supply energy, the system performance is significantly improved, and high efficiency and environmental friendliness are achieved.
Owner:大连葆光节能空调有限公司

Improved active-disturbance-rejection position controller for direct current (DC) motor, and design method of improved active-disturbance-rejection position controller

InactiveCN106788036AReal-time estimateEliminate in real timeElectronic commutation motor controlVector control systemsDifferentiatorControl variable
The invention discloses a structure and a design method of an improved active-disturbance-rejection position controller for a direct current (DC) motor; the DC motor is taken as a controlled object, and an output position signal is taken as a controlled variable; the controller mainly consists of four parts, i.e., a tracking differentiator, a nonlinear state error feedback part, an extended state observer and a disturbance compensation part. The improved active-disturbance-rejection position controller is mainly used to improve a fal function in a nonlinear function in the extended state observer, and the fal function is used to determine the tracking performance of the extended state observer and the controller; the concrete improvement measure is adding a linear feedback area into non-linear feedback; therefore, the problem that in the traditional method, timely control cannot be realized when the system error is too large and the gain is too low can be solved on the basis of guaranteeing system stability. By comparing simulation lines obtained before and after the improvement for the controller, the structure and the design method which are provided by the invention are proved to accelerate the output signal response speed under the condition that the position error of the DC motor is larger, thus improving the integral control performance of a system.
Owner:NANJING UNIV OF POSTS & TELECOMM

Data buffering system with load balancing function

The invention provides a data buffering system comprising a data buffering manager, a data buffering library and a load balancing processor, wherein the data buffering manager receives a data acquiring request from outside, and responds to the data acquiring request to send a data acquiring command to the data buffering library to judge if the data buffering library preserves corresponding data, if the data buffering library preserves the corresponding data, the data buffering manager gets the corresponding data back, and if the data buffering library does not preserve the corresponding data, the data buffering manager sends a database server acquiring request to the load balancing processor; the data buffering library responds to a data storage command to store data which need to be buffered in blocks and pages and also responds to the data acquiring command to send the corresponding data to the data buffering manager; the load balancing processor responds to the database server acquiring request to provide a database server which processes fewest request to the data buffering manager, and the load balancing processor acquires data and returns the data to be stored into the data buffering library according to the information of the database server. The invention enhances the memory utilization factor, reduces the interactive communication capacity, decreases the using inquiry times and the magnetic disc access times and enhances the system stability and the system operation efficiency.
Owner:YONYOU NETWORK TECH

Dual-redundancy attitude control system and debug method of coaxial unmanned helicopter

The invention discloses a dual-redundancy attitude control system of a coaxial unmanned helicopter, which consists of a serial communication module, a PCM (Pulse-Code Modulation) decoding module, an AD acquisition module, a PWM (Pulse-Width Modulation) output module and a CPU control module. The serial communication module, the PCM decoding module and the AD acquisition module are used as system input, the CUP control module carries out improved digital PID control, and the PWM output module carries out output in the form of PWM pulses, and thus, the control of a backward-stage high power valve is realized. A debug method comprises the following fives steps of: firstly, connecting a defined I/O port to a high or low-level end according to a parameter debug object; secondly, adjusting a potentiometer to provide initial parameters for Kp and Kd and controlling the backward-stage high power valve; thirdly, keeping a neutral position of Futaba unchangeable, adjusting the potentiometer so that a steering engine achieves a critical state of self-excitation vibration; fourthly, operating the Futaba to output a signal exceeding a pulse threshold; and fifthly, operating the Futaba to return to a central position. The method realizes the debug and the storage of relevant parameters, decreases interference and improves the system stability and the response speed.
Owner:BEIHANG UNIV

Dual-redundancy steering engine controller

The invention discloses a dual-redundancy steering engine controller, which belongs to the technical field of aviation flight control. A central control unit is a DSP chip digital signal processor, and PWM signals output by a plurality of paths of output ports of the central control unit are isolated by a photoelectric isolation unit, and then are divided into two groups and are input into a first set of power drive unit and a second set of power drive unit which consist of power drive chips and H bridge circuits and have same circuits respectively; drive power supplies of the two sets of power drive units and the voltage output to a steering engine (M) are switched by a fault switching unit controlled by the digital signal processor; a steering engine signal conditioning unit consisting of a steering engine current conditioning unit and a steering engine position conditioning unit is connected between the steering engine and an input end of the digital signal processor; and an RS422 serial port communication interface circuit unit is arranged between the digital signal processor and a host computer. The dual-redundancy steering engine controller has the advantages of simple structure, high control accuracy, good system stability, strong interference resistance, high reliability, low development cost and the like.
Owner:CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST

Driving method and system of four-rotor-wing unmanned flight vehicle

The invention discloses a driving method and a system of a four-rotor-wing unmanned flight vehicle. The method comprises the following steps that: navigation information is planned by a ground station according to a topographic map, and the navigation information is transmitted to a machine-mounted automatic driving control unit; after the flight vehicle is started, a sensing data automatic analysis processing unit generates current flight vehicle data according to current status information of the flight vehicle and transmits the current flight vehicle data to the machine-mounted automatic driving control unit; and the machine-mounted automatic driving control unit controls the flight vehicle to fly according to the navigation information and the current flight vehicle data. A flight path of the unmanned flight vehicle is planned on a target map, a plurality of discontinuous flight points are planned on the flight path, so the driving problem of the four-rotor-wing unmanned flight vehicle can be solved, advantages such as high reliability and high safety can guarantee the completion of different tasks, and advantages such as high hardware integration degree, high flexibility, high system stability, low maintenance cost and the like can be realized.
Owner:FOSHAN AIRCAM UAV TECH CORP

Nonlinear robust controller design method based on back-stepping and sliding mode control technologies and aimed at nonlinear model of quad-rotor unmanned plane

The invention discloses a nonlinear robust controller design method based on back-stepping and sliding mode control technologies and aimed at a nonlinear model of a quad-rotor unmanned plane. A sliding mode controller of a speed-constant reaching law is designed to an attitude angle system of the quad-rotor unmanned plane, and rapid tracking for the attitude angle is ensured. To realize track tracking for the spatial position of the quad-rotor unmanned plane, a sliding mode surface and a virtual control quantity are constructed according to a stepping back control idea to realize nonlinear control law design and system stability design from the kernel to the external layer of a system. After an equation of the related virtual control quantity is obtained, an expected track value of the attitude angle is obtained by solving the equation via arithmetic inverse operation, and a design method of the speed-constant reaching law is used to determine a final input control law of the quad-rotor unmanned plane system. According to the method of the invention, the characteristic that sliding mode control is uncertain for the model and insensitive to external interference is utilized, robust trace tracking for the nonlinear quad-rotor unmanned plane can be controlled under interference.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Distributed uplink unloading strategy for mobile edge computing

ActiveCN108809695AData switching networksDrift plus penaltyEdge server
The invention discloses a distributed uplink unloading strategy for mobile edge computing. The invention obtains an adaptive computing unloading strategy based on the Lyapunov theory and a proposed deviation degree update decision algorithm DUDA. The strategy comprises two main aspects: first, obtaining an optimal unloading decision set of users in Small Cells based on the Lyapunov theory on the premise of ensuring the system stability and minimized overhead; and secondly, proposing the DUDA to decide an unloading decision update sequence of the Small Cells in each time slot according to the deviation degree; and in the distributed uplink unloading strategy disclosed by the invention, it is considered that a user terminal has partial task unloading capability, that is, the tasks of a single users can be subdivided, a part of tasks are selected for local calculation according to specific application requirements and available resources with the target of minimizing the system overhead,and the remaining tasks are unloaded to an edge server of a Macro Cell in the HetNet scene. According to the distributed uplink unloading strategy disclosed by the invention, the system stability andthe optimal overhead are ensured by determining a drift penalty function, and an optimal unloading strategy set of users in the Small Cell under the condition is obtained.
Owner:ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +2

Self-adaptive wireless charging system

The invention discloses a self-adaptive wireless charging system, comprising an alternating-current power supply, a load, an AC (alternating current)/DC (direct current) conversion module, a driving module, a driving coil, an emitting coil, a receiving coil, a load coil, a rectifying module, a receiving end impedance matching module and a feedback control module, wherein the alternating-current power supply is connected with the driving coil by the AC/DC conversion module, the driving module, the emitting end impedance matching module and the driving coil that are sequentially connected with one another; the driving coil is coupled with the emitting coil; the emitting coil can transfer energy to the receiving coil by magnetic resonance coupling; the receiving coil is coupled with the loadcoil; the load coil is connected with the load by the rectifier module and the receiving end impedance matching module that are connected with each other sequentially; and the receiving end impedancematching module is connected with the driving module by the feedback control module. The self-adaptive wireless charging system can control the transmitting power of the wireless power supply, can improve the stability and running efficiency of the system, can improve the power factor of the system by a power compensation unit, and can reduce energy loss.
Owner:WUHAN ZHONGYUAN ELECTRONICS GRP

Quick client development frame for manufacturing execution system and software development method for frame

The invention relates to a quick client development frame for a manufacturing execution system and a software development method for the frame. The frame comprises a client layer and a service layer, wherein the client layer is used for realizing client interface interaction and comprises an interface view layer, an interface model layer and a model; and the service layer is used for realizing a business logic and data storage, receiving data sent by a client, reconstructing the data of the client according to a business requirement and sending the data to a database. The software development method for the frame comprises the steps of determining a data structure and the business logic of a development page as needed; designing UML class graph automatic generation codes; adding the codes into corresponding layers of project engineering in sequence; and compiling the project engineering to generate system software. According to the frame and the method, the code writing workload of the manufacturing execution system can be greatly reduced and the code quality and the system stability can be improved; and meanwhile, by applying a layered architecture and a configuration file, the software generated by the frame can be conveniently transplanted in different database systems.
Owner:SHENYANG INST OF AUTOMATION - CHINESE ACAD OF SCI

Two quantum cascade laser spectrum-based multicomponent gas simultaneous detection device and method

The present invention relates to the technical field of laser spectrum detection and gas detection, and in particular relates to a two quantum cascade laser spectrum-based multicomponent gas simultaneous detection device and method. An arbitrary waveform function generator outputs a periodic signal which only superposes high-frequency modulation signals in any half period to be used as a laser current signal, a room temperature continuous mode mid-infrared quantum cascade laser is driven by a current control unit, the laser emits a laser signal, the laser signal passes sequentially through a focusing collimating three-dimensional adjustment system, a first mirror, a sample absorption pool and a off-axis parabolic mirror to be reflected to a first detector, the first detector passes the laser signal through a data acquisition unit to convert into an electrical signal and transmit to a computer, and information of the gas to be measured can be obtained by analysis and processing of the electrical signal by the computer. The devices simultaneously utilizes two spectrums for gas detection, and has the advantages of high detection sensitivity, high detection accuracy, no need of external standard gas calibration, simple optical path adjustment, fast response, and stability, and the like.
Owner:ANHUI UNIVERSITY

Two-stage photovoltaic grid-connected control system based on combination of pole allocation and repetitive control

The invention relates to a two-stage photovoltaic grid-connected control system based on the combination of pole allocation and repetitive control, which can invert the direct current output by a photovoltaic cell into alternating current well and transmit the alternating current to a power system, so that the harmonic wave content is low, the power supply quality is good, the utilization ratio of a system is high, the stability of the system can be improved to a certain extent and the properties of the whole photovoltaic system are improved. The two-stage photovoltaic grid-connected control system based on the combination of pole allocation and repetitive control has the advantages that: (1) due to the adoption of numerical control, the antijamming capacity is high and the system can achieve high precision and stability; (2) the system has clear assignment, obvious control effect, reliability and high robustness, wherein a preceding-stage Boost converter can realize maximum power tracking; and a last-stage inverter achieves direct current side voltage stabilization and grid-connected inversion; and (3) a control algorithm is advanced, wherein a dead zone effect of the inverter and the harmonic wave caused by partial non-linear loads are avoided by a repetitive control technique; and precise control is realized through the state feedback-based pole allocation.
Owner:TIANJIN UNIVERSITY OF TECHNOLOGY
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