133 results about "Forced oscillation" patented technology

An impulse-type "wave motor" employs a seabed-mounted or supported structure mounting a wave energy absorbing panel on a hinged lever arm for reciprocation motion to obtain optimal absorption of wave energy from wave motion in the sea. For deepwater wavelengths of L, the panel is optimally positioned in a region within L/2 depth from the sea surface. The panel motion is coupled by a connecting rod to a fluid pump which generates a high-pressure fluid output that may be used to drive a reverse osmosis desalination unit or to produce other useful work. Seawater or brackish water may be desalinated through reverse osmosis membranes to produce water quality for consumption, agricultural, or other uses. The submerged operating environment of the device in a region of one-half the design wavelength provides the maximum available energy flux and forced oscillations. The pump may be of the positive-displacement piston type, plunger type, or multi-staging driver type, or a variable volume pump.

A DC power converter consisting of a series-resonant branch used to transform a DC voltage source into a DC current source exhibiting, a uni-polar, zero-current-switching characteristic. Frequency of the series-resonant branch, acting in concert with reflected load parameters, provides a forced oscillation frequency, Fo, component to an AC voltage source generated across the input winding of a power transformer by the resonant capacitor. Complex load parameters allow AC input current, displaced by 90° from the AC voltage source, to flow in the transformer primary winding throughout a composite, carrier-frequency cycle. Another component of the carrier-frequency consists of a resonant, natural oscillation frequency, Fn, resulting from resonance by the AC voltage source capacitance with the open-circuit inductance of the primary winding on the input power transformer. The composite carrier-frequency, Fo+Fn, transported through the input power transformer is directed to a rectifier/filter assembly and applied as a DC voltage to an output load. Thus, the uni-polar DC series-resonant branch is converted into an AC power transfer function, fully isolated from the input power switch, by the AC voltage source capacitor. The power transfer function characterizing a bi-polar power inverter requires a single power switch referenced to the input power return bus.

Oscillation damper with variable damping force, comprising a valve device, in which an actuator for adjusting the valve device performs a rotary motion against the spring force of a torsion spring, the position of the valve device being determined from the manipulated variable of the actuator and the reaction force of the torsion spring.

The present invention relates to a fluid treatment system comprising: an inlet; an outlet; and a fluid treatment zone disposed between the inlet and the outlet. The fluid treatment zone has disposed therein: (i) an elongate first radiation source assembly having a first longitudinal axis, and (ii) an elongate second radiation source assembly having a second longitudinal axis. The first longitudinal axis and the second longitudinal axis are non-parallel to each other and to a direction of fluid flow through the fluid treatment zone. The present fluid treatment system has a number of advantages including: it can treat large volumes of fluid (e.g., wastewater, drinking water or the like); it requires a relatively small “footprint”; it results in a relatively lower coefficient of drag resulting in an improved hydraulic pressure loss/gradient over the length of the fluid treatment system; and it results in relatively lower (or no) forced oscillation of the radiation sources thereby obviating or mitigating of breakage of the radiation source and/or protective sleeve (if present). Other advantages are discussed in the specification.

A technique in which a false detection and a wrong diagnosis can be suppressed in a capacitance sensor represented by an acceleration sensor is provided. A first capacitative element and a second capacitative element, which configure a capacitance detection unit, and a third capacitative element and a fourth capacitative element, which configure a forced oscillation generation unit, are electrically separated from each other. That is, the diagnosis movable electrode that configures the third capacitative element and the fourth capacitative element is formed integrally with the movable part. On the other hand, the diagnosis fixed electrode and the diagnosis fixed electrode are electrically separated from the detection fixed electrode and the detection fixed electrode.

The invention discloses a method for implementing a power system stabilizer. The method includes steps of acquiring a rotation speed variable quantity via a blocking filter link according to the rotation speed and active power of a rotor of a power generator, and respectively acquiring low-band differential signals, medium-band differential signals and high-band differential signals via a differential filter; parallelly adding the low-band differential signals, the medium-band differential signals and the high-band differential signals together to acquire rotation speed variation comprehensive signals of the power generator; measuring phase-shift characteristics of the rotation speed variation comprehensive signals and the rotation speed and uncompensated phase-shift characteristics of an excitation control system of the power generator by a forced oscillation process, computing required phase-shift characteristics among the rotation speed variation comprehensive signals and the power system stabilizer, designing multi-order lead-lag link phase-shift parameters which are serially multiplied by one another, performing phase compensation to meet the required phase-shift characteristics; finally outputting signals of the power system stabilizer and superposing the signals of the power system stabilizer on a reference voltage of an excitation regulator of the power generator. The method has the advantage that active power low-frequency oscillation of the synchronous generator can be effectively suppressed.

The invention provides a WAMS (wide area measurement system) and SCADA (supervisory control and data acquisition) integrated data based grid forced oscillation source positioning method. Oscillation sources are positioned rapidly and accurately by comprehensive utilization of data of the WAMS and SCADA. According to a main principle, the method includes: firstly, positioning general directions of the oscillation sources by adopting an energy flow function method based on 500kV grid WAMS data, then adopting different accurate oscillation source positioning methods according to properties of three common oscillation sources, computing tie lines of a local weak tie network by adopting an SCADA data based oscillation extreme point judgment method, and judging whether oscillation exists in the weak tie network or not; adopting WAMS data of generator excitation voltage phase to judge whether oscillation is caused by a generator excited system or not; adopting an extreme point computation method of SCADA data of valve or guide vane opening of a generator set to judge whether grid oscillation is caused by a unit prime mover or not.

The Bridge Tower Vast Utilities comprise:

• • multilevel blocks of recreation and pleasant entertainment arenas by usage the unique qualities of bridges as attracting, uniting structures which people always like to visit and enjoy,
  • high-efficient energy contributors,
  • reliable technological protection from forced oscillations, caused with gusty winds, traffic vibroeffects, earthquakes, by self-dampening flexible anti-resonance structures of the combined bridge tower column and poly flexible foundation.

The swimming pools, observation lots, orchards, children centers, aquarium, jet-yacht station, parking lots, ramps, elevators, infrastructures are combined with regular transportation and architectural means of civil bridges into an integrated system. This proposal provides much shorter and faster rate period of investment returns by effective and full serving for customers and owners with natural unique substance and attractive utilities of new and reconstructed civil bridges, which could be converted into well-desired and high-profit structures.

The invention provides a system and method for judging negative damping oscillation and forced oscillation based on a second order difference method. The method for judging the negative damping oscillation and the forced oscillation based on the second order difference method mainly comprises the following steps of: triggering start calculation according to an active power signal curve for hinge nodes, the frequency of transformer substation bus voltage or connecting lines, generator outlets and active power signals of the generator outlets through break-variable of current; finding out peaks of the signal curve by a sampling comparison method; calculating a first order difference value and a second order difference value of peak power in the first several or more than a dozen of cycles at the beginning of increasing oscillation, and comparing the symbols of the first order difference value and the second order difference value; if the first order difference value and the second order difference value are same in symbol, judging to be the negative damping oscillation; and if the first order difference value and the second order difference value are different in symbol, judging to be the forced oscillation. A corresponding alarm signal is given by a monitoring host according to the property of the oscillation so as to dispatch operating personnel to rapidly take the measure of restraining low-frequency oscillation, or a command of the measure of restraining the low-frequency oscillation is directly given, thereby, the safe and reliable runnability of a power grid is enhanced.

The invention discloses a circulation control device and a method of an induction electric power transmission system, which belong to the field of induction electric power transmission control. The circulation control method provides a method for obtaining frequency difference and frequency compensation direction between a forced oscillation frequency and an inherent resonance frequency accordingto a circulation duration time and a voltage peak value, wherein the method comprises the following steps of: obtaining the circulation duration time through a first current transformer and a first comparator; then obtaining a circulation peak value by means of FPGA (Field Programmable Gate Array); obtaining the frequency difference compensation direction through a second current transformer and a second comparator; judging whether the bidirectional circulation is mutated trough a differentiating circuit and a third comparator by means of FPGA, wherein when the bidirectional circulation is mutated, an AD (Average Deviation) collector is controlled to collect the voltage peak value which is corresponding to the bidirectional circulation by means of FPGA; and then recording the times for reaching to the circulation peak value in two close times by the FPGA, and obtaining the frequency difference by calculating according to the circulation peak value and the voltage peak value. The circulation control device and method of an induction electric power transmission system provided by the invention have the advantages that the purpose for accurately controlling the circulation in an induction electric power transmission system is achieved by the using of a circulation control device with low hardware requirement and a sample circulation control method.

A forced oscillation demonstration test instrument comprising a base frame, a displacement sensor, a spring oscillator (spring and mass block) and a propulsion unit, wherein the voltage between the two poles of the spring oscillator is in proportional to the tension force, and the spring tension force is proportional to the displacement of the oscillator mass. When the coil is powered by alternating current, the counteracting force of the ampere force exerted on the coil will be the driving force for the excitation of spring oscillator oscillating, the driving force signal can be represented by the voltage on the resistor in series connection with the coil.

A self-actuated cylinder comprising a cylinder housing comprising electro-magnetic force generating means to generate electro-magnetic forces, and a piston within the cylinder housing, wherein the electro-magnetic forces act directly on the piston to displace the piston within the cylinder housing. The self-actuated cylinder can be used as an oscillation spirometer to determine air flow, an input impedance or Forced Oscillation pulmonary mechanics.

The invention discloses a dynamic response testing device for a deep-sea elongated vertical pipe under vertical forced oscillation. By the dynamic response testing device, vortex-induced vibration testing of the vertical pipe under vertical forced oscillation action can be realized, safety coefficient in large pipe mounting can be increased by fully utilizing a lifting pedestal of an oceaneering deepwater pool, real Reynolds number vortex-induced vibration of the large pipe can be simulated by fully utilizing depth of the oceaneering deepwater pool, realtime monitoring equipment can be arranged around the large pipe by fully utilizing width of the oceaneering deepwater pool, and shape of a model can be adjusted according to different needs. Due to adoption of modularized design, the dynamic response testing device has the advantages that the dynamic response testing device is convenient to mount, upgrade and modify and meets different functional requirements.

Disclosed is a Hamming formula-based milling stability predicting method. The Hamming formula-based milling stability predicting method is mainly applied to selecting reasonable milling parameters for part machining. The Hamming formula-based milling stability predicting method is characterized by comprising dispersing a forced oscillation period into evenly-spaced intervals through the Hamming formula to obtain the transfer matrix of a milling system, and determining the characteristic value of the transfer matrix of the milling system according to the Fourier theories to predict the stability of the milling system. During high-speed numerical controlled machining processes, the Hamming formula-based milling stability predicting method can help select reasonable milling parameters according to a stability labe graph to ensure achieve high-speed and high-efficiency machining without oscillation, thereby optimizing machining parameters, ensuring high surface quality and achieving precise machining.

The invention discloses a method for locating a forced oscillation disturbance source in a doubly-fed wind farm. The method constructs an energy function of a doubly-fed wind-driven generator, can determine whether a disturbance source is located on the doubly-fed wind-driven generator, and can further determine the position of the disturbance source inside the generator if so. The method can locate the disturbance source inside the doubly-fed wind-driven generator just by providing the structure and parameter information of an induction generator without the information such as a control modeand the structure of the wind-driven generator, and has a certain universality in a context where various wind-driven generator control modes are provided and a prime mover is complicated in structure. The method can accurately determine the position of the disturbance source inside the wind-driven generator, reflects the situation that each component inside the wind-driven generator participatesin the forced oscillation, and provides convenience for optimizing the structure and control mode of the wind farm.

The invention relates to a method for evaluating forced oscillation influence in an interconnected large power grid. The method includes the following steps: A. determining a typical operation mode of a power system; B. obtaining an oscillation mode of a power grid to be researched and a characteristic of the oscillation mode; C. finding out units corresponding to forced oscillation having the largest influence on a generator set, a local power grid and the interconnected power grid and disturbing signal characteristics of the units; D. summarizing a general characteristic rule of the forced oscillation influence. By means of the method, the defect that the existing evaluating method only considers section low-frequency oscillation frequency and only aims at influence of the forced oscillation on a large power grid is overcome, stable parameters of the generator set can be checked by combining practical recording data, the method has the advantages of being good in generality and adaptation, comprehensive in considering factors and reasonable in scheme, facilitating fast decision making and the like and has high practical value and good market prospects.

A radiation curable inkjet printing method for producing printed flexible foils and plastic bags includes the steps of a) providing a web-like polymeric substrate having a maximum value for Tan δ between 40° C. and 110° C.; b) providing a single pass inkjet printer having at least one page-wide printhead or at least one set of staggered printheads, a transporting device arranged to transport the web-like recording medium, and a curing device; c) jetting onto the web-like polymeric substrate having a surface energy Ssub, a non-aqueous radiation curable inkjet liquid having a surface tension SLiq, wherein SLiq is smaller than SSub by at least 4 mN/m; and d) curing the radiation curable liquid on the substrate at a surface temperature equal or higher than the temperature of the maximum value for Tan δ and smaller than the melting point of the polymeric recording medium. The maximum value for Tan δ is determined by dynamic mechanical analysis at a temperature ramp of 3° C./min using forced oscillation with a cycle of 1 second and an amplitude of 100 μm. Also, a single pass inkjet printer for performing the method.

Provided are a wide scope oxygen sensor aging monitoring system for a vehicle and a fault diagnosis method. An engine and a sensor executor, an ECU and a wide scope oxygen sensor intelligent driver chip and the like thereof are utilized, and aging monitoring is performed on a wide scope oxygen sensor. The ECU is responsible for detecting and determining aging faults of the wide scope oxygen sensor, utilizing forced oscillation to compare lambda signals and lambda reference signals actually collected from the wide scope oxygen sensor, a minimum slope ratio between the lambda signals and the lambda reference signals is compared, and whether the wide scope oxygen sensor has the aging faults is determined according to the slope ratio. The system can accurately detect the aging faults of the wide scope oxygen sensor and is applicable to all vehicles where the wide scope oxygen sensor is installed.

The invention discloses a forced oscillation disturbance source identification and splitting method based on an oscillation starting characteristic and belongs to the technical field of emergency adjustment and control in an electric power system. According to the method, the oscillation starting characteristic of forced oscillation and a disturbance source location energy function method are combined, the correct position is identified from a plurality of suspected disturbance source areas, and if the disturbance source area meets the condition of electric energy supply and demand balance and no island exists in the non-disturbance source areas, a connection fracture surface line between the area where a disturbance source is located and a system can be split; otherwise, the identified area where the disturbance source is located serves as an initial island, adjacent nodes of the island are searched for, and the connection fracture surface is adjusted till the requirement for electric energy supply and demand balance is met and the condition that power grids remaining after splitting are connected is met. The method solves the problem about positioning of the disturbance source in forced oscillation control. Through the method, splitting control measures can be given in real time when oscillation is detected, and the method has great significance in suppressing oscillation and guaranteeing stable running of interconnected electric power systems.