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85results about How to "Suppress shock" patented technology
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Excitation state analysis-based low-voltage ride-through control method of virtual synchronous power generator
ActiveCN107591839AEliminate negative effectsSuppress inrush currentSingle network parallel feeding arrangementsReactive power adjustment/elimination/compensationVirtual synchronous generatorRe engineering
The invention discloses an excitation state analysis-based low-voltage ride-through control method of a virtual synchronous power generator. The method comprises the steps of improving designs of droop characteristic, a reactive power ring and an active power ring by means of a reactive power adjustment principle of the synchronous power generator and a power grid which are connected in parallel,and the problems of excessive large reactive power increment, difficulty in preventing impact current and loop coupling reinforcement are effectively dealt with; and on the basis of no change on characteristic of the state analysis-based low-voltage ride-through control method of virtual synchronous power generator (VSG) system, an additional current ring is designed again, the under-excitation state running of an auxiliary system can be assisted during power grid fault period, an output current is adjusted, and a reactive power support is given out. A new directional method is employed, the transient process is accelerated, a control algorithm is not needed to be switched during the power grid fault period, a smooth switching strategy among states is also not needed to be added, and the low-voltage ride-through problem and the asymmetric drop of the power grid can be simultaneously dealt with.
Owner:JIANGSU UNIV
Stirred tank reactor simulation method based on immersed boundary method
ActiveCN105069184APromote generationReduce workloadSpecial data processing applicationsBoundary knot methodSolid particle
The present invention provides a stirred tank reactor simulation method based on an immersed boundary method. The method includes: a preparation phase including determination and setting of calculating parameters, generation of fluid grid files, generation of Lagrange mark point information, and preparation of calculating resources; numerical calculation: setting boundary conditions of computational domains and solving velocity fields and temperature fields based on fluid grids; combining with a discrete element method to achieve an interface analytic simulation of two-phase flow of particle flow, wherein the immersed boundary method is directly employed to apply non-slip boundary conditions to particle surfaces; a post-processing phase, and outputting information of each Euler mesh and information of each particle after a simulation is completed. According to the characteristics of different boundaries, in the calculation, the mixed immersed boundary method is employed to process, and the mass numerical simulation of turbulent flow in the stirred tank reactor is achieved through combination of large eddy simulation and high performance parallel computing technology. The simulation method may be applied to simulation of turbulent flow and simulation of solid particle suspension in the stirred tank reactor and the like.
Owner:INST OF PROCESS ENG CHINESE ACAD OF SCI
Control System for Supercharged Internal Combustion Engine
ActiveUS20080022678A1Suppress shockEmission is deterioratedElectrical controlInternal combustion piston enginesIgnition timingBypass valve
A control system for a supercharged internal combustion engine provided with a main exhaust passage (20) extending through a turbocharger turbine (21) and further through a catalyst (23, 24) to open to the outside air, an exhaust bypass passage (25) by passing the turbocharger turbine by branching from the main exhaust passage at the upstream side of the turbine and merging with the main exhaust passage before reaching the catalyst at the turbine downstream side, and an exhaust bypass valve (26) provided at the exhaust bypass passage, the control system for a supercharged internal combustion engine controlling the ignition timing in accordance with at least one of the engine warmup state and the catalyst warmup state until warmup of the internal combustion engine and warmup of the catalyst are completed and further controlling the opening degree of the exhaust bypass valve based on the control of the ignition timing, is provided.
Owner:TOYOTA JIDOSHA KK +2
Method for determining stability of small interference of direct-current power grid
ActiveCN106712067ASimplify the commutation processEasy to set upElectric power transfer ac networkTransient stateMathematical model
The invention provides a method for determining stability of small interference of a direct-current power grid. A main circuit of a modular multi-level converter is equivalent to a simplified equivalent model; a converter electromagnetic transient model and a converter controller system are established and then are processed by linearization to obtain an active power small interference basic mathematical model; a small interference linearization Thevenin equivalent model of a converter and a small interference linearization generalized mathematical model of a direct-current power grid are established; and a small interference stability determination basis of the direct-current power grid is obtained. According to the determination method, the architecture is clear and simple; the method is easy to understand; the internal commutation process of the converter is simplified; a mathematic model can be established and analyzed conveniently. A small interference linearization model of a converter can be popularized and restriction of the original equivalent model is broken through, so that the method is suitable for all work conditions; and the direct current oscillation can be suppressed and a stability analysis can be realized conveniently. And a reliable and accurate basis for studying the mutual influence of alternating-current and direct-current power grids is provided, so that the operation reliability of the alternating-current and direct-current power grids can be improved.
Owner:GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +2
Segmented resistance type IGBT driving circuit and control method thereof
InactiveCN106656130AIncrease device application frequencyReduce switching lossesElectronic switchingPush pullEngineering
The invention discloses a segmented resistance type IGBT driving circuit, which is characterized in that a segmented resistor driving circuit comprises a plurality of segmented resistors which are connected in series, both ends of each segmented resistors are connected with a bypass MOS transistor in parallel; each bypass MOS transistor and a driving push-pull circuit are connected with a driving controller; and an IGBT gate clamping circuit comprises an IGBT gate voltage-stabilized clamping circuit and an IGBT gate power supply clamping circuit. The invention further discloses a control method of the segmented resistance type IGBT driving circuit, which is characterized in that a pulse rising edge and a falling edge are driven at the gate, and the size of the gate driving resistance is changed through switching of the bypass MOS transistors. The segmented resistance type IGBT driving circuit and the control method thereof can achieve the purposes of reducing the switching loss of an IGBT device and improving the application frequency of the device while ensuring suppression for surge and gate oscillation.
Owner:NANJING NARI GROUP CORP
SOC estimation method for lithium iron phosphate battery pack
ActiveCN109031147AConducive to continuationAffect the estimation accuracyElectrical testingWeight adjustmentEngineering
The invention provides a method for estimating SOC of a lithium iron phosphate battery pack using a BP neural network. The BP neural network adopts a hidden layer, three inputs, and one output networkstructure, and the number of nodes of the hidden layer is 11. The estimation method comprises the following steps: adjusting a connection weight adjustment link of the BP neural network, inserting aninertia coefficient, using smooth weighted calculation to improve the connection weight adjustment, increasing an original connection weight item when performing the connection weight adjustment calculation, and giving a heavier weight. The method uses the current integral correction method to change the parameters of the BP neural network, which reduces the influence of the capacity decay of thelithium iron phosphate battery pack on the SOC estimation accuracy.
Owner:湖南安华源电力科技有限公司
Backward discrete state event-driven power electronic simulation method, device and medium
ActiveCN107290977ASolve processing problemsAvoid enumerationSimulator controlDesign optimisation/simulationNumerical stabilityState variable
Owner:TSINGHUA UNIV
Body Dampener
InactiveUS20120066809A1Reduce vibrationSuppress shockEye treatmentProtective garmentEngineeringShock absorber
The Body Dampener is comprised of vibration and shock dampening flexible band, a fastening apparatus, a vibration and shock dampening device, and vibration and shock dampening filaments and is wrapped around an extremity of the human body to offer compression, vibration dampening, and directs vibration out of the body. The vibration and shock dampening device is attached to the vibration and shock dampening flexible band. The vibration and shock dampening filaments are attached to the vibration and shock dampening device or the vibration and shock dampening flexible band. The vibration and shock dampening filaments protrude outward away from the body directing vibration out of the body.
Owner:GOTH JOHN +1
Temperature control method based on symbol identification in cable current-carrying capacity heat cycling test
InactiveCN102707745AImprove robustnessSuppression temperatureTemperature control using electric meansTemperature controlCarrying capacity
The invention relates to a temperature control method based on symbol identification in a cable current-carrying capacity heat cycling test, symbol value computing is carried out on the acquired temperature and current, the symbol value which reflects the current temperature control state is obtained, the target parameters are upgraded after the symbol value judgment, a voltage regulator motor is controlled to rotate positively and negatively, the temperature rising and reducing control is realized, after the temperature reaches the set state, the symbol values of temperature and current signals are repeatedly extracted, the motor is controlled again to operate, and accordingly, the quick stable temperature control process is realized. By the temperature control method, the temperature of a cable conductor in the cable current-carrying capacity heat cycling test is quickly stabilized at the set value, the temperature control process has better robustness, the temperature overshoot and oscillation are suppressed, the whole control process is simple to realize, has less calculations and exact control logic, and can be widely applied to the conductor temperature control or the constant value control of variable parameters with the similar requirements.
Owner:UNIV OF SHANGHAI FOR SCI & TECH
Permanent-magnet synchronous motor control system and method
ActiveCN107134954ASuppress fluctuationsSuppress shockTorque ripple controlMotor control for motor oscillations dampingStator voltageControl system
The invention discloses a permanent-magnet synchronous motor control system and method. The system comprises a lifting speed controller, a V / F curve controller, an SPWM modulator, a voltage source inverter, a permanent-magnet synchronous motor, a coordinate transformation circuit, a voltage compensation circuit and a rotational-speed compensation circuit. The V / F curve controller obtains a compensated rotational speed according to a given rotational speed and a compensating rotational speed; the V / F curve controller obtains given voltage according to the compensated rotational speed and a V / F control curve; the SPWM modulator obtains compensated voltage according to the given voltage and compensating voltage; the SPWM modulator conducts sinusoidal pulse width modulation on the compensated voltage to obtain a modulation signal; the voltage source inverter conducts inversion according to the modulation signal to obtain three-phase current and outputs the three-phase current to the permanent-magnet synchronous motor. According to the permanent-magnet synchronous motor control system and method, through the rotational speed compensation and stator voltage compensation of the permanent-magnet synchronous motor, the changes of reactive power are inhibited, the reactive power of the system is kept unchanged, and therefore the fluctuation of reactive current and the oscillation of the system are inhibited, and the system runs smoothly.
Owner:中山长峰智能自动化装备研究院有限公司
Active damping control method for active third harmonic injection matrix converter
The invention relates to an active damping control method for an active third harmonic injection matrix converter, and belongs to the technical field of the control method for the active third harmonic injection matrix converter. According to the method, adding a virtual damping branch on the input side of the active third harmonic injection matrix converter to obtain the virtual damping current by differentiating the power supply current, and using the relationship between the input side and the third harmonic injection current to correct a third harmonic injection current reference value, thereby improving the damping of the input filter d and suppressing the filter oscillation. According to the active damping control method for the active third harmonic injection matrix converter, the input side filter damping is improved, at the same time, the problem that the passive damping method reduces the efficiency and increases the high harmonic content of the input current is avoided, andthe method is important to improve the stability, efficiency and power supply current quality of the active third harmonic injection matrix converter.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
Damping device for electric mechanical equipment
InactiveCN109296885APrevent looseningAvoid safety hazardsNon-rotating vibration suppressionStands/trestlesElectric machineryEngineering
The invention provides a damping device for electric mechanical equipment, and relates to the technical field of electric mechanical equipment, in particular to a damping device for electric mechanical equipment. The damping device comprises a base plate; a fixed clamp plate and a fixed plate are fixedly connected to the upper surface of the base plate in sequence from left to right; one side of the fixed clamp plate is fixedly connected with a first pressure spring; one side of the first pressure spring is fixedly connected with a first support plate; a hole is formed in one side of the fixedplate; a first bearing is inserted in the hole; a connecting rod is movably connected to the inner wall of a second bearing; a first rotating rod is fixedly connected to one end of the connecting rod; and one end of the first rotating rod is fixedly connected with an output end of a first motor. In the damping device for the electric mechanical equipment, through the effect of a damper, the damping effect is achieved; when a pressure block is suffered from vibration of the base plate, the vibration is transferred to a damping spring; and the damping spring inhibits the rebound oscillation after vibration absorption.
Owner:STATE GRID CORP OF CHINA +1
Wind turbine generator optimization control method based on multi-objective model prediction
ActiveCN112019113ASuppress shockObjective function optimizationElectronic commutation motor controlVector control systemsEngineeringPermanent magnet synchronous generator
The invention relates to the field of wind power generation and discloses a wind turbine generator optimization control method based on multi-objective model prediction. According to the method, basedon conventional virtual inertia control, a current loop with finite set model predictive control is adopted, and current, frequency and electromagnetic torque are used as optimization objectives, sothat the control has the characteristic that multiple objectives are optimized at the same time, the stability of the frequency is effectively enhanced in a frequency disturbance process, and meanwhile shafting oscillation caused by disturbance is restrained; on the basis of a conventional constant weight coefficient, dynamic weight coefficient control is realized through a power function structure; the weight coefficient of each optimization objective can be adjusted under different working conditions, the stability of a wind power generation system is further enhanced; the designed control structure enables a permanent magnet synchronous generator set to have higher inertia and frequency supporting capacity, and the stability of the system is improved while virtual inertia is obtained.
Owner:HEFEI UNIV OF TECH
High-frequency intermittent control system and method for bidirectional series resonant converter
ActiveCN112311245AReduce lossRealize functionEfficient power electronics conversionDc-dc conversionHemt circuitsEngineering
The invention discloses a high-frequency intermittent control system and method suitable for a bidirectional series resonant converter. The high-frequency intermittent control system comprises a firstfilter circuit, a first inverter / rectifier circuit, a resonant circuit, a high-frequency transformer, a second inverter / rectifier circuit, a second filter circuit, a voltage and current acquisition circuit, a controller and a drive circuit. The bidirectional series resonant converter can realize voltage reduction and voltage boosting functions at the same time, a relatively wide working range isrealized, all switches realize wide-range zero-current switching, and the switching loss is reduced. Pulse control is added in the switching period, and the pulse can reach half of the resonant frequency, so that the voltage ripple is reduced. The control strategy can enable the system to have a linear power transmission characteristic, and the system has simple characteristics and is easy to operate.
Owner:CHINA UNIV OF GEOSCIENCES (WUHAN)
Optimization control method suitable for UHVDC commutation failure fault recovery
ActiveCN113098045AReduce marginClear recovery control objectivesElectric power transfer ac networkPower oscillations reduction/preventionDc currentControl engineering
The invention discloses an optimization control method suitable for UHVDC commutation failure fault recovery. The method comprises the following steps: 1, acquiring a DC voltage, a DC current, a converter turn-off angle and a bus phase voltage of an AC system at an inverter side of a UHVDC system in real time; 2, constructing dynamic current margin control by using a difference value between a rectification side-direct current instruction value and an inversion side direct-current measurement value and a slope of a current margin function; and 3, after the fault is cleared, through the inverter side converter, adopting constant current control to make the dynamic current margin control take effect, so that the current margin in the fault recovery process is reduced. According to the method, the direct-current control target in the UHVDC system low current recovery process can be determined, so that the probability of unstable recovery of the system caused by improper interaction of the rectification side constant current controller and the inversion side constant current controller is reduced, and the subsequent commutation failure generated in the UHVDC fault recovery process is effectively inhibited.
Owner:HEFEI UNIV OF TECH +2
Oscillation restraining method and device for train traction system
ActiveCN108656963ASuppress shockSolve Compatibility IssuesSpeed controllerPropulsion using dc motorsCapacitanceTraction system
The invention provides an oscillation restraining method and device for a train traction system. The oscillation restraining method comprises the steps that the distortion degree of the input tractionvoltage, the distortion degree of the supporting capacitor side voltage and the distortion degree of the input current of a current transformer are calculated; according to the distortion degree of the input traction voltage, the distortion degree of the supporting capacitor side voltage and the distortion degree of the input current, a first traction brake level signal is corrected, and thus a second traction brake level signal is obtained; and according to the second traction brake level signal, the output torque of a traction motor is adjusted. According to the oscillation restraining method and device for the train traction system, characteristic contents corresponding to the input traction net voltage, the supporting capacitor side voltage and the input direct current of the tractioncurrent transformer in the train traction system are monitored, the distortion degrees of the corresponding net voltage, the corresponding voltage and the corresponding current are calculated according to the corresponding characteristic contents, the backward stage output torque of the traction current transformer is finely adjusted according to the distortion degrees, and accordingly oscillation on the direct current side of the traction system is restrained.
Owner:CHINA CREC RAILWAY ELECTRIFICATION BUREAU GRP
Diesel generator set with protection device
InactiveCN110410626AAvoid multiple shocksEnsure transportation safetyNon-rotating vibration suppressionEngine bedsEngineeringDiesel generator
The invention discloses a diesel generator set with a protecting device. The diesel generator set comprises a bottom plate, wherein a supporting table is arranged on the bottom plate, a generator setis placed on the supporting table, a supporting plate is installed at the lower end of the generator set, baffles are rotationally connected to the two sides of the supporting table, two damping mechanisms are symmetrically installed on the bottom plate, and limiting blocks are symmetrically welded at two ends of the middle of the supporting table. According to the diesel generator set with the protection device, when the generator set vibrates, a connecting plate and a movable rod are driven to displace, and the vibration can be absorbed through damping springs; meanwhile, the movable rod drives a piston to move in a buffer base, so that the movement resistance of the movable rod is increased, so that the vibrate caused by rebound of the damping springs after vibrate absorption is inhibited, and the generator set is prevented from being vibrated for multiple times during bumping, so that the transportation safety of the generator set is ensured.
Owner:JIANGSU TAIPU POWER MACHINERY
Dynamic response active control method and device for brushless double-electromechanical-port motor
ActiveCN111277191ASolve the shockSuppress shockElectronic commutation motor controlAC motor controlLoad torqueGear wheel
The invention discloses a dynamic response active control method and device for a brushless double-electromechanical-port motor, and belongs to the field of AC motors and drive control. According to the method, double three-phase windings are used for supplying power to generate a magnetic field with two pole pairs, which respectively act on a magnetic gear MGM and a permanent magnet synchronous motor PMSM part, thereby achieving the active control over dynamic response of an outer rotor driving shaft of a brushless double-electromechanical-port motor under current closed-loop tracking. Specifically, on the basis of a few-pole magnetic field torque prediction method, deadbeat compensation control over the outer rotor driving shaft is achieved when an inner rotor suddenly increases and decreases loads, and the system response is greatly enhanced; through a load torque observation method on the outer rotor driving shaft, the feedforward compensation control during sudden loading and sudden unloading on the outer rotor driving shaft is realized, and the system response is further enhanced. Control is simple and easy to achieve, system oscillation can be effectively restrained, systemresponse is improved, and the service life is prolonged.
Owner:HUAZHONG UNIV OF SCI & TECH
Satellite network routing oscillation inhibition method and system
ActiveCN108011661AReduce the number of routing optionsSuppress shockRadio transmissionData switching networksRoute flappingPredictability
The invention provides a satellite network routing oscillation inhibition method and system. The system comprises the following steps: S1, computing link survival time of an adjacent inter-rail link,wherein the link survival time is the time interval of the adjacent inter-rail link to the link interrupting moment from the current moment, and positioning a care-of link in routing oscillation basedon the link survival time; S2, eliminating the link delay change of the care-of link through a link cost function to eliminate the influence on the routing selection by the link delay change, therebyrealizing the routing oscillation inhibition. The link survival time can be computed through the predictability of the satellite movement, and the care-of link in the routing oscillation is positioned; and the link cost function only acted on the care-of link is proposed and used as the basis of the routing computation; the link cost function can decouple the linkage change relation of the link delay and the link connectivity on the basis of maintaining relatively changed spatial network topology, thereby eliminating the factors causing the routing oscillation.
Owner:TSINGHUA UNIV +1
Elevator starting control method and system
InactiveCN109969880APrevent rolling phenomenonSuppress shockElevatorsBuilding liftsElectric machineryStable state
The invention relates to the technical field of elevator control, in particular to an elevator starting control method and system. The method comprises the following steps that the torque of a motor is compensated by a first PI adjuster, whether the movement of an elevator exceeds a preset first threshold value or not is detected after an elevator brake is opened, if yes, the torque of the motor is compensated by a second PI adjuster, and meanwhile, PI adjusting parameters of the first PI adjuster and PI adjusting parameters of the second PI adjuster are increased; otherwise, the current PI adjusting parameters of the first PI adjuster is kept to compensate the torque of the motor until the starting process is ended; and when the second PI adjuster is used for compensating the torque of the motor, whether the elevator vibrates or not is detected, and if yes, the PI adjusting parameters of the first PI adjuster and the PI adjusting parameters of the second PI adjuster are reduced. The elevator control method and system can be used for detecting and adjusting different load conditions in the elevator starting process, a stable state can be rapidly achieved when the elevator is started under any load condition, and the comfort of passengers is improved.
Owner:SHENZHEN HPMONT TECH
Crusher gear static pressure bearing mechanism
InactiveCN103410955AAvoid wear and tear or even failureIncrease stiffnessGear lubrication/coolingEngineeringCrusher
The invention discloses a crusher gear static pressure bearing mechanism which comprises a static pressure bearing ring. The static pressure bearing ring is of an annular shape, the inner hole of the static pressure bearing ring is in a stepped shape, and dowel holes are formed in the stepped face of the inner hole in the circumferential direction. An annular oil storage tank is formed in the end face of a small hole diameter end of the static pressure bearing ring in the circumferential direction, the end face of the small hole diameter end of the static pressure bearing ring is divided into an inner ring face and an outer ring face through the annular oil storage tank, and a plurality of radial oil discharging tanks communicated with the annular oil storage tank are uniformly distributed in the inner ring face and the outer ring face in the circumferential direction respectively. According to the crusher gear static pressure bearing mechanism, the operating principle of hydrostatic static pressure bearing is utilized, namely a continuous and stable fluid pressure source is directly injected into a bearing face at the lower end of the static pressure bearing, fluid with definite pressure is supplied between friction surfaces, loads are borne with the help of static pressure of the fluid, gluing and fast abrasion of a bevel gear static pressure bearing piece and a backup washer are effectively prevented, and thus stability and reliability of transmission of a bevel gear are guaranteed.
Owner:CITIC HEAVY INDUSTRIES CO LTD
Rectification power supply, novel radar power distribution system control device and strategy
ActiveCN110601562AAvoid damageImprove reliabilityAc-dc conversion without reversalTransmission systemsCapacitanceRadar
The invention relates to a rectification power supply. The rectification power supply comprises an input power supply, a soft start circuit, a rectifying circuit, an output contactor KM03 and a control circuit; the output end of the input power supply is electrically connected with the soft start circuit; the soft start circuit is electrically connected with the rectifying circuit; the rectifyingcircuit is electrically connected with the output contactor KM03; one end of the control circuit is electrically connected with the soft start circuit; the other end of the control circuit is electrically connected with the output contactor KM03; and the output contactor KM03 is also connected with external equipment through a capacitor. The invention further discloses a novel radar power distribution system control device and strategy. By means of the rectification power supply, the novel radar power distribution system control device and strategy in the invention, oscillation can be suppressed in the input voltage range of an array DC / DC converter; and the problem of loss, even failure, due to the fact that the input-end voltage of the array DC / DC converter forms oscillation by long-wiretransmission can be effectively solved.
Owner:CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST +1
Sidewall inclined X-ray layered multilayer film grating structure
ActiveCN109243661AIncrease effective penetration depthHigh resolutionHandling using diffraction/refraction/reflectionHandling using diaphragms/collimetersGratingImage resolution
The invention relates to a sidewall inclined X-ray layered multilayer film grating structure comprising periodically distributed multilayer film stacks. The central position of the multilayer film stacks coincides with the central position of each grating period, and the wide ratio of the multilayer film stacks monotonically increases from the top to the bottom, wherein the wide ratio refers to the ratio of the lateral width of the multilayer film stacks to the grating period at any height position of the multilayer film stacks, and the thickness of the periodic film layers also monotonicallyvaries from the surface to the substrate. Compared with the structures in the prior art, the shortcomings of the conventional sidewall vertical high-aspect-ratio layered multilayer film grating structure that is difficult to manufacture and poor in mechanical stability can be overcome, the stability and the service life of the grating elements can be remarkably improved and the highest efficiencyof the grating remains unchanged; besides, the film stack structure of which the upper part is narrow and the lower part is wide can further improve the effective penetration depth of X-rays so that higher resolution and spectral purity can be obtained. The structure can be used as the key reflective element for high-resolution X-ray spectrum measurement.
Owner:TONGJI UNIV
Auxiliary winding current control method and device for variable-speed constant-frequency water pumping energy-storage system
ActiveCN109687800AAccelerate the transient processSuppress shockAC motor controlPolyphase induction motor starterElectrical resistance and conductanceConstant frequency
The invention provides an auxiliary winding current control method and device for a variable-speed constant-frequency water pumping energy-storage system. The auxiliary winding current control methodcomprises the following steps: a current working stage of the variable-speed constant-frequency water pumping energy-storage system is determined; and an auxiliary winding current generated by the variable-speed constant-frequency water pumping energy-storage system is controlled according to the current working stage. According to the auxiliary winding current control method, by using an auxiliary winding structure and controlling the auxiliary winding current when the system is in the different stages, the problems of small torque, low efficiency and large heating in the traditional resistorshort-circuit starting process are avoided, especially heavy-load starting of the system is facilitated, in the low-voltage crossing process of the system, stator flux linkage oscillation is inhibited, the motor transient process is accelerated, the overcurrent risk of a rotor current is lowered, and the low-voltage crossing ability is improved.
Owner:TSINGHUA UNIV +1
Self-adaptive virtual synchronous generator cascade micro-grid control method
PendingCN114389307ASuppress shockImprove frequency stabilityFlicker reduction in ac networkSingle network parallel feeding arrangementsVirtual synchronous generatorDefuzzification
The invention discloses a self-adaptive virtual synchronous generator cascade micro-grid control method. A fuzzy controller is adopted to control a virtual synchronous generator cascade micro-grid. The input quantity of the fuzzy controller is omega s, domega / dt, and the output quantity of the fuzzy controller is delta J and delta D; omega s is angular frequency deviation; domega / dt is an angular frequency change rate; delta J is the variable quantity of the virtual inertia; delta D is the variable quantity of the damping coefficient; performing normalization processing on omega s and domega / dt by using quantization factors k1 and k2; the fuzzy controller obtains delta J and delta D through a given fuzzy rule and defuzzification reasoning. According to the change rule of the angular frequency change rate and the angular frequency variation of the synchronous generator, the oscillation period is subdivided and improved, the fuzzy rule table is redesigned, and the virtual inertia and the damping coefficient are adjusted, so that the control effect of the VSG is improved.
Owner:CENT SOUTH UNIV
High-voltage DC power supply, high-voltage pulse modulator and radiotherapy equipment
InactiveCN110635708ASuppress shockPulse generation by energy-accumulating elementX-ray/gamma-ray/particle-irradiation therapyModulation patternVIT signals
The invention relates to a high-voltage DC power supply, a high-voltage pulse modulator and radiotherapy equipment. The high-voltage DC power supply comprises a capacitor charging circuit, a feedbackcircuit and a modulation circuit, wherein the capacitor charging circuit is used for charging the capacitor, and the capacitor discharges to the outside after being charged; the feedback circuit is connected with the capacitor charging circuit and the modulation circuit and is used for acquiring circuit parameters of the capacitor charging circuit and transmitting the circuit parameters to the modulation circuit; the modulation circuit is connected with the capacitor charging circuit and used for collecting circuit parameters of the capacitor charging circuit, adjusting a modulation mode according to the circuit parameters, generating a modulation signal according to the circuit parameters and the adjusted modulation mode and transmitting the modulation signal to the capacitor charging circuit. Thus, the modulation mode of the modulation circuit is adjusted according to the circuit parameters, and a modulation mode is switched when the power supply is about to finish charging, so thatvoltage oscillation is suppressed, and high-precision voltage control is realized.
Owner:SHANGHAI UNITED IMAGING HEALTHCARE
Ship inclination test device
The invention discloses a ship inclination test device which comprises a water tank, a suspension rod, a pendulum bob, a rope and a plurality of wave absorbers, the water tank is used for containing water, the suspension rod is fixed on the outer wall of the water tank, the pendulum bob is suspended on the suspension rod through the rope and immersed in the water in the water tank, each wave absorber comprises a plurality of blades, and the wave absorbers are arranged on the inner wall of the water tank. At least part of the blades are immersed in water. According to the ship inclination test device, water is adopted to replace heavy oil to immerse the pendulum bob, the difficulty of inclination test preparation work is reduced while pollution is avoided, due to the fact that the viscosity of water is low, water in the water tank is prone to oscillation in the inclination test process, the pendulum bob cannot be stabilized within a long time. According to the ship inclination test device, the wave absorbers are arranged on the inner wall of the water tank, and the blades of the wave absorbers can interact with water to inhibit water oscillation, so that the pendulum bob can be stabilized in a short time, and the efficiency of an inclination test is further improved.
Owner:GUANGZHOU SHIPYARD INTERNATIONAL LTD
Overvoltage protection circuit for substation and application thereof
PendingCN109494701ASuppression of energy shocksFor equipment maintenanceEmergency protective arrangements for limiting excess voltage/currentThree-phasePower substation
The invention discloses an overvoltage protection circuit for a substation and an application thereof. The overvoltage protection circuit comprises a three-phase inlet-line side circuit, a three-phaseoutlet-side circuit and a star type connection circuit with a neutral point. The three-phase inlet-line side circuit is formed by successive series connection of three-phase inlet line ends A1, B1 and C1, a three-phase linked disconnecting switch S1 and a three-phase damping resistor R1. The three-phase outlet-side circuit is formed by successive series connection of three-phase outlet line endsA2, B2 and C2, a three-phase linked disconnecting switch S2 and a three-phase damping resistor R2. Wires a, b, and c are connected with three-phase input terminals of the star type connection circuit;each phase of circuit of the star type connection circuit is connected in series with a damping resistor R3; and the neutral point of the star type connection circuit is grounded through a damping resistor R3. According to the invention, the overvoltage protection circuit having a simple structure is designed ingeniously; and overvoltage protection against the ground short circuit faults betweena bus circuit breaker and an outlet line is realized.
Owner:国网湖北省电力有限公司黄石供电公司 +2
Linear continuous static force loading control method
ActiveCN109372826AEliminate opening reduction factorsSuppress shockFluid-pressure actuator testingLoop controlHigh pressure
The invention discloses a linear continuous static force loading control method for a nonlinear integration element-free hydraulic loading system. The linear continuous static force loading control method comprises a precise linear continuous static force loading control method, a method of improving the linearity of the static force loading process and a method of achieving continuous loading inthe static force loading process. The linear continuous static force loading control method provided by the invention meets the precise linear continuous static force loading demand of an active pressure storing function free hydraulic device of a small high pressure hydraulic cavity and also meets the precise linear continuous static force loading demands of other nonlinear or integration element-free hydraulic devices. The linear continuous static force loading control method primarily aims to solve the problem that the static force cannot be precisely and linearly loaded in a load open-loop control process by taking a load as a control quantity and a proportional overflow valve as an executing element and solves the problem that the static force cannot be loaded continuously as a result of load value oscillation in an existing load closed ring control process taking the load as a control quantity, a proportional overflow valve as an executing element and a real-time load as a feedback quantity.
Owner:INST OF CHEM MATERIAL CHINA ACADEMY OF ENG PHYSICS
Gate turn-off control method and device of silicon carbide field effect transistor and driving circuit
InactiveCN109831197ASuppress shockAvoid damageElectronic switchingField-effect transistorControl equipment
The invention discloses a grid turn-off control method. The grid turn-off control method comprises the steps of obtaining parasitic parameters of a silicon carbide field effect transistor; judging themonotonous relationship between the overshoot voltage and the gate turn-off voltage of the silicon carbide field effect transistor according to the parasitic parameters; determining an optimal valueof the gate turn-off voltage in a preset value interval according to the monotonic relationship, wherein the gate turn-off voltage enables the overshoot voltage to obtain the minimum value in the interval at the optimal value; and outputting the gate turn-off voltage with the optimal value to the gate of the silicon carbide field effect transistor so as to turn off the silicon carbide field effecttransistor. According to the invention, the gate turn-off voltage with a small overshoot voltage value is selected to carry out turn-off control on the silicon carbide field effect transistor, so that the crosstalk problem is solved, the drain-source voltage oscillation can be effectively inhibited, the device damage phenomenon caused by overshoot voltage is avoided, and the circuit operation safety is ensured. The invention also discloses a gate turn-off control device of the silicon carbide field effect transistor and a driving circuit, which also have the above beneficial effects.
Owner:湖南德雅坤创科技有限公司
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