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140results about How to "No overshoot" patented technology

Device and method for controlling single-bus modular digital actuator of robot

The invention relate to a device and a method for controlling a single-bus modular digital actuator of a robot. The device comprises an actuator control unit, a direct-current motor, a communication module, a speed reduction mechanism, position and temperature sensors and a current protection circuit. The method includes that the actuator control unit computes control parameters according to the running temperatures, driving currents of the motor and the position of the actuator and outputs the control parameters to a motor control circuit; the communication module receives control instructions of an upper computer and feeds information of the current position of the actuator, the current speed of the actuator and the like to the upper computer; a high rotational speed and low torque of the motor are converted into a low rotational speed and high torque by the speed reduction mechanism and an output mechanism, and the low rotational speed and the high torque are outputted by the speed reduction mechanism and the output mechanism; the position sensor, the temperature sensor and the current protection circuit are respectively used for feeding current position signals of the actuator, the running temperatures and the driving currents of the motor to the actuator control unit, so that closed-loop high-precision safety control can be implemented. The device and the method have the advantages of overcurrent, overvoltage and over-temperature protection, capability of preventing overload or over-temperature damage, high response speed, zero dead zones and high control precision.
Owner:UBTECH ROBOTICS CORP LTD +1

Permanent-magnet synchronous motor torque control system and method based on a sliding-mode observer and auto-disturbance rejection control

The invention discloses a permanent-magnet synchronous motor torque control system and method based on sliding-mode observer and auto-disturbance rejection control, so that the torque of the permanent-magnet synchronous motor is controlled rapidly and precisely. A minimal-order extended flux-linkage sliding-mode observer is designed; an auto-disturbance rejection current controller is designed; difference processing is carried out on an electromagnetic torque outputted by an observer and a given torque signal outputted by an upper computer and the difference is inputted into a PI controller; a q-axis current signal outputted by the PI controller and dq-axis flux-linkage component outputted by the observer are inputted into the auto-disturbance rejection current controller to form a torque closed loop. According to the permanent-magnet synchronous motor torque control system and method, the dynamic response of the output torque of the motor is accelerated and no overshoot phenomenon is avoided. Moreover, on the basis of combination of the sliding-mode observer and the auto-disturbance rejection controller, the reliability and robustness of the torque control of the permanent-magnet synchronous motor are enhanced. The permanent-magnet synchronous motor torque control system and method are applied to occasions with the permanent-magnet synchronous motor as a driving system.
Owner:HUNAN UNIV OF TECH

Method for optimizing brushless DC motor fuzzy controller based on improved particle swarm algorithm

The invention discloses a method for optimizing a brushless DC motor fuzzy controller based on an improved particle swarm algorithm. The steps include that the whole solution space is divided into seven areas; adaptation degree of each particle is calculated according to a target function; the individual extremum of the particles and the global extremum are updated according to adaptation degree; the updated individual extremum and the global extremum are assigned to quantifying factors Ka and Kb and scaling factors Kp, Ki and Kd; and input and output performance indicators are assessed, if the input and output performance indicators meet the target function, the process ends, and if the input and output performance indicators do not meet the target function, Pi and Pg are substituted in a quantum particle swarm formula by applying the improved particle swarm algorithm, continuous optimization of the particles is performed in the space areas until the particles meet the target function and new particle swarms are generated. The globally optimal solution can be found out at the highest speed based on the improved particle swarm algorithm, and a motor stably operates under the rated rotating speed and is rapid in response without overshoot basically so that the method has great follow-up performance and dynamic and static characteristics.
Owner:GUANGXI NORMAL UNIV

Auto disturbance rejection control technology-based direct-current busbar voltage control method of high-voltage chain-type STATCOM (Static Synchronous Compensator) power unit module

The invention relates to an auto disturbance rejection control technology-based direct-current busbar voltage control method of a high-voltage chain-type STATCOM (Static Synchronous Compensator) power unit module. Capacitors at the direct-current side of a chain-type STATCOM are mutually independent; the individual unit module has direct-current capacitor loss difference, switch loss difference, drive pulse delay time difference, and the like in the running process; the voltage of the direct-current capacitor of each chain-type STATCOM unit module is unbalanced and has difference, so that harmonic contents of an output voltage and an output current of the chain-type STATCOM unit module are influenced, even the normal and safe operation of the chain-type STATCOM unit module is endangered. According to the method disclosed by the invention, an auto disturbance rejection controller does not need to judge the instantaneous current direction; after parameters are accurately set, the disturbance quantity contains active components with active fluctuation; and the auto disturbance controller can achieve the purposes of high response speed and no overshoot of voltage of the unit direct-current capacitors due to the existence of a tracking differentiator and a nonlinear controller.
Owner:JIANGSU WEIFAN INTELLIGENT ELECTRICAL TECH

Method for controlling radial basis function (RBF) neural network tuned proportion integration differentiation (PID) and fuzzy immunization

The invention relates to a method for controlling radial basis function (RBF) neural network tuned proportion integration differentiation (PID) and fuzzy immunization. A main loop adopts RBF neural network tuned PID control, and inputs of an RBF neural network comprise an error e and an output measured value yout; kp, ki and kd are obtained by calculation; after the variables are input to the PID control for carrying out calculation, a variable u1 is output; a subloop adopts fuzzy immunization control, the fuzzy immunization control adopts an error e2 output by the PID control and the variation rate as inputs, and an output is a nonlinear function f(x), and the fuzzy immunization control is used for controlling the subloop by immune calculation; and the control is applied to a serial control system so that the system hardly has overshoot in the process of transition and is more stable.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Auto-disturbance rejection position servo system optimization design method based on improved CPSO

The invention discloses an auto-disturbance rejection position servo system optimization design method based on an improved CPSO. By aiming at problems of permanent magnet synchronous motor servo systems on high position control precision, fast response, and stable performance, a double-loop control structure is adopted, and a PMSM auto-disturbance rejection position servo control system is established. By aiming at a parameter setting problem of an auto-disturbance rejection position controller, the improved Chaos Particle Swarm Optimization (CPSO) is provided. By adopting the CPSO, a position of a particle is initialized according to cubic chaotic mapping, and an index self-adaptive way having adjustable parameters is used to adjust inertia weight in a non-linear way, and at the same time, the position of the particle is updated by adopting a chaos and stability alternate way, and therefore the convergence rate and the global optimization ability of the CPSO are effectively improved, and the CPSO is used for the optimization of the auto-disturbance rejection position controller parameters. By combining with a fitness function including position control requirements, the optimization design of the PMSM position servo control system is realized, the position control precision and the response speed of the servo system are improved, and a strong disturbance rejection ability is provided.
Owner:WUXI XINJIE ELECTRICAL

Self-adaptive PID (proportion integration differentiation) temperature control method

The invention discloses a self-adaptive PID (proportion integration differentiation) temperature control method, which comprises the following steps of: step 1, collecting a temperature in real time; step 2, calculating a heating speed in real time; step 3, adjusting a PID parameter according to the real-time heating speed; step 4, carrying out PID arithmetic; and step 5, converting the result of the PID arithmetic into continuous control on a time quantum, and directly controlling the switching on and the switching off of the working current of a heater strip by using a bidirectional silicon controlled rectifier. The technical effects of the self-adaptive PID temperature control method lie in that the heating speed is calculated in a heating process; a control parameter is adjusted dynamically, so that the heating process is more stable; the algorithm is subjected to multiple tests on a plurality of different instruments at different ambient temperatures; results show that an appointed temperature can be stably achieved in a heating way; an overshoot phenomenon cannot appear in the heating process; and the precision meets a system requirement.
Owner:湖南迪斯生物技术股份有限公司

LED (Light Emitting Diode) driving circuit

The invention discloses an LED (Light Emitting Diode) driving circuit. According to the LED driving circuit disclosed by the invention, whether the LED driving circuit works in a soft starting state or not can be judged by comparing a first threshold value with a soft starting reference value, the inductive current and the LED driving current can be subjected to soft starting in stages during a soft starting process, thus the overshoot of the inductive current and the LED driving current can be effectively restrained, and the continuous stable start of the LED driving circuit can be realized; and in addition, the end of the work of a soft starting circuit can be controlled by a comparing result of the first threshold value and the soft starting reference value, the end of the soft starting work state can be automatically judged without an external device, and the controllability is strong.
Owner:SILERGY SEMICON TECH (HANGZHOU) CO LTD

Method for controlling piezoelectric valve positioner capable of changing PWM (pulse-width modulation) duty ratio

The invention relates to a method for controlling a piezoelectric valve positioner capable of changing PWM (pulse-width modulation) duty ratio. A software system is formed by a main monitoring program module, an initializing module, a parameter self-tuning module, a valve position control module, a man-machine interaction module, an interrupt processing module, an EEPROM (electrically erasable programmable read-only memory) storage module and a watchdog module. Positive PWM duty ratio is changed by adding a five-step switch method with negative PWM into a sectional PI method or a linearization method, and when the control method is applied to small-range step control, positive PWM pulses with big duty ratio can be obtained, valve position starting process can be accelerated, the number of positive PWM pulses and adjusting time of small-range step control can be reduced, and small-range step control process can be accelerated.
Owner:HEFEI UNIV OF TECH

Multi-agent auto-disturbance time-varying formation tracking and collision avoidance control method under obstruction of obstacle

The invention discloses a multi-agent auto-disturbance time-varying formation tracking and collision avoidance control method under obstruction of an obstacle. The multi-agent system is composed of amoving target and N-1 agents with the numbers to be 1 to N in sequence. Each agent in the multi-agent system has a target tracking capability. Considering the diversity of system execution tasks and the limitation of the number of formation members, only one agent performs the target tracking task at one moment, the agent is called a tracking main agent, and other agents perform other tasks. Through local information interaction between neighbor agents, the subsystem (1-2) can track the state of the target. The auto-disturbance control theory is used to solve the disturbance suppression problem, collision avoidance control is realized based on a potential field method, and a topology switching strategy is adopted to ensure target tracking continuity.
Owner:ROCKET FORCE UNIV OF ENG

Temperature control method and system of microwave oven, and microwave oven

The invention discloses a temperature control method and a system of a microwave oven, and the microwave oven. The method comprises the following steps of: collecting a microwave oven temperature in stages; comparing an oven temperature and a set temperature through a (Proportion Integration Differentiation) PID instruction, obtaining a deviation value, carrying out the PID calculation and processing on the deviation value to obtain a corresponding controlled quantity; regulating a power of a microwave source based on the controlled quantity; and controlling a temperature of the microwave oven based on the regulated power output by the microwave source. Temperature control accuracy of the microwave oven is increased, thus, problems of high-cost implementation manner of a PID control method, complicated operation steps, heavy-workload microwave oven and a large quantity of manpower and financial resources wasting in the prior art are solved.
Owner:湖南阳东微波科技有限公司

LED control circuit

The invention discloses a light emitting diode (LED) control circuit. The LED control circuit comprises a drive circuit, a charging circuit and an LED which are connected in turn, wherein the drive circuit is started by a pulse width modulation (PWM) signal; the drive circuit enables the charging circuit to output an LED current to the LED; and after the charging circuit is on, the LED circuit rises. The LED control circuit also comprises a charging accelerating circuit A, wherein the charging accelerating circuit A is triggered and started by the PWM signal, keeps conduction in a period that the LED current is output till the LED current starts to rise, and generates a current input to the charging circuit to ensure that the charging circuit quickly reaches a threshold value voltage to enter a conducting state. The LED control circuit has the advantages of obviously shortening current output delay time, improving the response speed of a system, effectively controlling LED current overshoot not to happen at an LED current advancing edge, and improving the linearity of brightness control of the LED in a PMW current regulation mode.
Owner:金峰

Pre-set performance trajectory tracking control method of ocean bottom flying node (OBFN) by considering propeller output saturation

The invention discloses a pre-set performance trajectory tracking control method of an ocean bottom flying node (OBFN) by considering propeller output saturation, relates to the pre-set performance trajectory tracking control method of the OBFN, and aims to solve the problem that current disturbance, modelling uncertainty, propeller fault, propeller output saturation and the like are not considered at the same time in the prior art. The method in the invention comprises the steps of: (1), establishing a Fossen-outline six-degree-of-freedom nonlinear dynamical model; (2), obtaining a dynamicalmodel of the OBFN, and determining the tracking error equation of the OBFN according to the dynamical model of the OBFN; (3), establishing a performance function; (4), performing error conversion on the tracking error in the step (3), so that the converted error s is obtained; (5), introducing propeller output saturation, and determining an auxiliary system used for processing propeller output saturation; and (6), designing an OBFN system total uncertainty observer and a pre-set performance trajectory tracking controller. The method in the invention is used in the field of trajectory trackingcontrol.
Owner:HARBIN ENG UNIV

Low-cost quick solidifying method for composite material

ActiveCN104827613AFast heatingGood uniformity of temperature fieldTemperature resistanceElectromagnetic induction
The invention relates to a low-cost quick solidifying method for a composite material. A middle-frequency electromagnetic induction coil directly acts on a metal mould to self heat and solidify to form a composite material, middle frequency heating speed is high, the uniformity of a temperature field is good, the control is exact, the temperature overshoot is small, the production efficiency is greatly improved, and the product quality is ensured; furthermore, by utilizing middle-frequency electromagnetic induction heating, only the self metal mould is heated, a non-metal auxiliary material for forming the composite material is not heated, and the ambient temperature is very low after a special coating is utilized in a forming process, so that a very expensive high-temperature-resistance auxiliary material is not necessary to use when a high-temperature-resistance composite material such as bismaleimide and polyimide is formed; therefore, the manufacturing cost is saved and the energy consumption is low.
Owner:AEROSPACE RES INST OF MATERIAL & PROCESSING TECH +1

Outer-level damping method of strap-down inertial navigation system based on adaptive complementation filtering

The invention discloses an outer-level damping method of a strap-down inertial navigation system based on adaptive complementation filtering, which belongs to the technical field of navigation strap-down inertial navigation. In the method, an adaptive complementation filtering technology is employed to reduce an initial error and an oscillation error. During a process of designing damping network,a complementation filtering technology is used to obtain the higher-order damping network; a relation between a damping parameter and an outer reference speed error is searched according to the outerreference speed error changed with time, and an relation expression formula is obtained; the damping parameter is substituted into the damping network, the damping network is introduced to a solutionloop of inertial navigation to obtain a new solution equation. The damping of adaptive complementation filtering damping network eliminates a Schuler oscillation error, an overshoot error due to damping switching and decentralization even divergency phenomenon due to change of the outer reference speed, so that the outer-level damping method has higher stability and practicality.
Owner:HARBIN ENG UNIV

Device and method applied in gradient temperature control

The invention provides a device applied in gradient temperature control. The device is composed of a first temperature control module, a second temperature control module, a control module, a transmission device or a rotation device, a controlled target and a detection module. The method and device of the invention has the advantage of good expandability, different temperature control modules can be alternately used at different time points, the temperature control module in the off-working state adopts the idle time to realize the next target temperature value, sudden changes do not needed, and the service life can be prolonged; the temperature control module in the working state does not undergo the temperature rising / falling process, so the sample module temperature rising / falling rate can be improved, the overshoot phenomenon can be avoided, and the complex control algorithm does not needed. The temperature control is more flexible, the effective temperature control time of the controlled target can be shortened, the temperature change rate of the controlled target can be improved, and the application in gradient temperature control can be realized. Less temperature control modules are adopted, and different temperature control modules are used to control the temperature of the controlled target in different time periods through the idea of 'time division multiplex access' so as to realize a plurality of target gradient temperatures.
Owner:ZHEJIANG UNIV

Subsection subsection sliding mode control and flying capacitor voltage balance method of three-level DC-DC buck converter

The present invention provides a subsection segment sliding mode control and flying capacitor voltage balance method of a three-level DC-DC buck converter. The method comprises: the step 1, building and modal analysis of the subsection sliding mode control system of the three-level DC-DC buck converter; the step 2, performing balance of the flying capacitor voltage while controlling the output voltage based on the subsection sliding mode control theory; and the step 3, performing efficient, rapid and stable control based on the subsection sliding mode control method.
Owner:CHONGQING UNIV

Intelligent swing gate system

The invention provides an intelligent swing gate system. The intelligent swing gate system comprises a control circuit and a gate machine with two gates, and further comprises two actuators and two motors. The gate machine is further provided with an information collection unit, and the information collection unit and the actuators are electrically connected with the control circuit; each actuator is electrically connected with one gate through one motor. The information collection unit obtains identity information of a user; the control circuit sends a gate opening or closing action instruction to each actuator according to the identity information; based on the sine and cosine acceleration and deceleration algorithm and a planned gate action curve, each actuator generates rotation information of the corresponding motor, and sends the rotation information to the corresponding motor; according to the rotation information, each motor drives the corresponding gate to be opened to a target position. The intelligent swing gate system is good in motion stability, synchronization of an opening position and a closing position can be ensured, the sine and cosine acceleration and deceleration algorithm is adopted, gate is opened or closed in place and accurately, the phenomena of overswinging, shaking and impacting does not occur, and the reliability and the user experience are improved.
Owner:深圳市嘉昱机电有限公司

Computer control system for novel direct drive lockstitch sewing machine

The invention relates to a computer control system for a novel direct drive lockstitch sewing machine. The computer control system comprises a master controller, a pedal speed regulator, an operation panel, solenoid valves, a power supply module, a motor, a motor drive controller and a photocoupling isolation module. The computer control system is characterized in that the master controller consists of a microprocessor CPU, a communication module, a driving module for the solenoid valves, a speed control module and a current control module; the microprocessor CPU realizes bi-directional data communication with the operation panel by a communication module circuit, realizes control and protection over actions of the solenoid valves of the sewing machine by a solenoid valve drive circuit, and realizes variable frequency control over the motor by the speed control module and the current control module; the master controller is respectively connected with the pedal speed regulator, the operation panel, the solenoid valves and the photocoupling isolation module; and the motor drive controller consists of a special servo drive module and a current detection module.
Owner:BEIJING TIANYU TECH INNOVATION

Two-stage three-phase four-bridge-arm inverter system with BOOST and control strategy thereof

The invention discloses a two-stage three-phase four-bridge-arm inverter system with BOOST and a control strategy thereof. The system comprises a BOOST DC-DC converter, a three-phase four-bridge-arm inverter, an LC filter, a sampling unit, a load unit, and a control chip. Direct current power supply passes through the BOOST DC-DC converter and direct current bus voltage is provided for the three-phase four-bridge-arm inverter. After the inversion of the direct current bus voltage by the three-phase four-bridge-arm inverter, the direct current bus voltage is filtered by the LC filter and then is connected to the load unit. A sampling signal obtained by the sampling unit goes through the filter and then is inputted into the control chip for processing. The control chip outputs an MOSFET driving signal, the MOSFET driving signal passes through an optocoupler isolation circuit and a MOSFET driving circuit and then is connected to the BOOST DC-DC converter and the three-phase four-bridge-arm inverter. According to the system and the control strategy, sequence component separation control based on three-dimensional space vector pulse width modulation technology is used, the symmetry of output voltage waveforms can be ensured by each harmonic compensation control, and problems of asymmetry and distortion of voltage waveforms in an asymmetric load and a nonlinear load are solved.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Method for maintaining operation of coal supply machine frequency transformer when switching instantly electric power of

The present invention relates to a technique for controlling the transducer of the coal supplying machine in the coal-fired power plant. A method for sustaining the operation when the electric power source of the transducer of the coal supplying machine is characterized in that the filtering capacitor C of the direct-current component DC on the main loop of the voltage type universal transducer is in parallel connected with an energy storing capacitor CS with corresponding electric capacitance according to the capacity magnitude of the load motor. An actuating charging resistor RS which has power matched with the resistance value according to the electric capacitance of the energy storage capacitor CS. Two routes of control electric power source of a control device and a control circuit of the coal supplying machine are provided with an UPS electric power source device. The technique according to the invention has the advantages of brief principle, smooth operation of the object driven by the transducer, good operability and safety, simple configuration and reliable electric power source.
Owner:BAOSHAN IRON & STEEL CO LTD

Power electronic converter control method based on transient electromagnetic energy balance

The invention relates to a power electronic converter control method based on transient electromagnetic energy balance, belonging to the technical field of power electronics. The power electronic converter control method based on transient electromagnetic energy balance is characterized in that the control objects of a power electronic converter are converted into the transient electromagnetic energy, the control objects of different dimensions are unified through the electromagnetic energy, the transient electromagnetic energy is adjusted in the dynamic-state process to track the target steady energy quickly, and the electromagnetic energy is kept in the allowed change range of the dynamic-output target energy value in the steady-state process. The power electronic converter control method based on transient electromagnetic energy balance can be applied to various power electronic converters. The experimental result proves that compared with the conventional control method, the power electronic converter control method based on transient electromagnetic energy balance helps to increases the dynamic response speed, eliminate the control overshoot and improve system reliability while guaranteeing the steady-state control precision.
Owner:TSINGHUA UNIV

Non-linear PID adaptive control method based on tracking differentiator

The invention discloses a non-linear PID adaptive control method based on a tracking differentiator. The method comprises the following steps of setting up the tracking differentiator TD; establishing a non-linear PID (NLPID) control law; and setting up an adaptive learning algorithm of an NLPID weight coefficient. The non-linear PID adaptive control method based on the tracking differentiator has great stability and convergence. Furthermore, the method which can accurately track reference signals achieves no overstrike and no oscillation and has strong robustness stability. Furthermore, the method has the characteristics of simple controller structure, clear theory model, no dependence on a controlled object model and low computational complexity. Therefore, the method is especially suitably used for real-time control on unknown objects or objects which are hard to model.
Owner:HUNAN UNIV OF TECH

Integrated control system and control method for adjustable optical attenuator

The invention relates to an integrated control system and control method for a variable optical attenuator. The system is provided with a configuration management module, an input quantity management module, an attenuation amount voltage lookup table, a first configurable timer, a second configurable timer, a third configurable timer, a table look-up management module, a PID (Proportion Integration Differentiation) input management module, a PID calculating speed management module, a PID calculating module and an output quantity management module. The method comprises the following steps of: starting the configuration management module; starting the input quantity management module; calculating a current actual attenuation amount; entering the table look-up management operation; entering the PID input management operation; calculating a current desired attenuation value and a current actual attenuation value; judging time timed by the second configurable timer; carrying out PID calculation; outputting a calculating result to the output quantity management module; calculating a current table look-up attenuation amount and a table look-up threshold set value; judging whether the current table look-up attenuation amount is less than or equal to the table look-up threshold set value or not; and judging whether time timed by the first configurable timer is up or not. By the integrated control system and control method, the control on different types of variable optical attenuators can be realized.
Owner:GUANGXUN SCI & TECH WUHAN

Micro gas turbine combined cooling and power control system and method based on generalized predictive control

The invention discloses a micro gas turbine combined cooling and power control system and method based on generalized predictive control. A prediction error calculation module based on an ARX model performs prediction error calculation according to the fuel amount and the rotational speed, and then a generalized predictive control module is switched on; a second module calculates the optimal fuelamount according to the deviation between the set value of the rotational speed and the actual rotational speed and the input of a third module; a prediction error calculation module based on a Hammerstein model performs the prediction error calculation according to the fuel amount, a valve opening degree of a smoke by-pass valve and the cold water temperature, and then a nonlinear generalized predictive decoupling control module based on the Hammerstein model is switched on; and a fourth module calculates the optimal valve opening degree of the smoke by-pass valve according to the deviation between the set value of the cold water temperature and the actual value, the control sequence of the fuel amount calculated by the second module and the input of a fifth module. The micro gas turbinecombined cooling and power control system and method based on the generalized predictive control effectively overcome the complex characteristics of a system and improve the flexibility and security of the system.
Owner:SOUTHEAST UNIV

Fuzzy adaptive PID control method for fuel cell voltage

The invention discloses a fuzzy adaptive PID control method for a fuel cell voltage. The method comprises the following steps of setting up a dynamic model of a fuel cell; carrying out a step responsetest on the dynamic model of the fuel cell, carrying out transfer function identification based on obtained response data through adoption of a least square method, and carrying out parameter settingof a PID controller through utilization of an identified model; and designing a fuzzy controller, carrying out fuzzification on the fuzzy controller according to a voltage error and a change rate ofthe voltage error, carrying out fuzzy reasoning and defuzzification according to a fuzzy rule, thereby obtaining correction parameters, and correcting a proportion coefficient and an integral coefficient, wherein differentiation action is realized according to a differentiation forward algorithm. According to the method, influence of fuel cell nonlinearity can be effectively suppressed, overshootis reduced, transition time is reduced, an integral saturation phenomenon and a jump phenomenon of differentiation action are overcome, and ideal control performance is achieved.
Owner:SOUTHEAST UNIV

Method for confirming wind tunnel shrink section curve

InactiveCN103500265ANo overshootThe curvature of the curve is completely continuousAerodynamic testingSpecial data processing applicationsEngineeringSupersonic speed
The invention provides a method for confirming a wind tunnel shrink section curve. According to the method, once an inlet size, an outlet size, a shrink section length and a curvature radius of a shrink section outlet are given, a cylindrical curve, a first biquadratic curve, a conic curve and a second biquadratic curve are sequentially arranged from an inlet of the shrink section, and the shrink section curve is obtained. The shrink section curve designed in the method is suitable for a subsonic speed wind tunnel and a supersonic speed wind tunnel, the whole curve curvature is completely continuous, the curvature of the inlet and the curvature of an outlet are the same as the curvature of a front element and the curvature of a rear element, and perfect connection is achieved. The front of the curve cannot shrink abruptly, an overshoot phenomenon cannot occur to the outlet, and defects of an existing shrink curve are overcome. Air flows of the outlet are evenly distributed.
Owner:BEIJING AEROSPACE YISEN WIND TUNNEL ENG TECH

Temperature control system for reflux welder

The invention discloses a temperature control system for a reflux welder, which comprises a programmable controller, a parameter setting unit, a plurality of temperature detection units and an upper monitoring machine connected with the programmable controller, wherein the plurality of temperature detection units are arranged in a plurality of temperature areas respectively; a plurality of electric heaters and a plurality of heating fans which are respectively arranged in the plurality of temperature areas are controlled by the programmable controller; a photoelectric probe is arranged on the reflux welder; a speed measuring probe is arranged on a traveling channel for work pieces inside the reflux welder; an electromagnetic switch for controlling and adjusting the heating power of the electric heaters is connected to a drive control circuit of the electric heaters in series, and the conduction angle of the electromagnetic switch can be controlled by the programmable controller. The temperature control system is reasonable in design, simple to operate and good in use effect, and solves the problem of large temperature fluctuation under large disturbance, and meanwhile, the problem of temperature control lag is solved, therefore, the temperature control system has the advantages that the heating speed is fast, no overshoot exists, the temperature fluctuation is small in the condition of inputting large work pieces, the cost is saved, and the like.
Owner:XIAN ZHONGKEMAITE ELECTRONICS TECH EQUIP

Flatness control method for modular multilevel matrix converter

The invention relates to a flatness control method for a modular multilevel matrix converter. The method comprises the following steps of 1) establishing a corresponding M3C mathematical model according to an M3C circuit topological structure; 2) performing double alpha beta 0 transformation on the mathematical model to obtain an M3C decoupling model comprising an input side decoupling model, an output side decoupling model, a bridge arm capacitor voltage and loop current decoupling model and a common mode voltage decoupling model; 3) performing dq conversion on the input side decoupling model, and constructing an input side flatness control strategy based on the feedforward reference control quantity and the error feedback compensation quantity; and 4) carrying out PI control on the output side decoupling model, the bridge arm capacitor voltage and the loop current decoupling model, and combining the input side flatness control strategy, the common-mode voltage control, the H-bridge sub-module voltage sharing control and the carrier phase shift modulation to jointly complete the flatness control of M3C. Compared with the prior art, the method has the advantages of quickening the global stabilization speed, having no static error in tracking, being high in dynamic performance and the like.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Cascaded H-bridge SVG system and method based on hybrid decentralized control

The present disclosure provides a cascaded H-bridge SVG system and method based on hybrid decentralized control. The system and method can realize active and reactive power control during a grid voltage sag, balance control of SVG output current, stability and balance control of the DC-side capacitor voltage, and has the advantages of low cost, high reliability and fast fault response.
Owner:SHANDONG UNIV +1
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