45results about How to "Improve frequency response performance" patented technology

The invention discloses an active frequency response event control strategy. The active frequency response event control strategy comprises: in an offline state, clustering all possible operation states of a power system according to selected frequency stability related state quantity to form several typical scenes, analyzing the typical scenes to determine an active frequency response control strategy of each scene to form a control decision table, determining the active frequency response event control strategy: dividing frequency fluctuation and evolution process of a power grid into two stages, namely, a frequency decline phase and a frequency recovery stage; and performing frequency control on the power grid by adopting an active frequency response event control mode in the frequencydecline phase and adopting a passive frequency response parameter feedback control mode in the frequency recovery stage. The control strategy provided by the invention can effectively intercept frequency decline in the frequency decline phase so as to avoid low-frequency load reduction of the system, and makes the system restore the stability in the frequency recovery stage as soon as possible toavoid frequency oscillation of the system in an active control process.

The invention provides a surface acoustic wave (SAW) resonator with accurately weighted reflecting grating array and metal dot arrays. The SAW resonator comprises a piezoelectric substrate, wherein a metal interdigital transducer and a reflecting grating are sputtered on the piezoelectric substrate; the reflecting grating comprises a first short-circuit grating and a second short-circuit grating which are arranged on left and right sides of the metal interdigital transducer respectively; the first short-circuit grating and the second short-circuit grating are symmetrically distributed on the left and right sides of the metal interdigital transducer; a metal dot array weighted by a weighting function is arranged on the first short-circuit grating and the second short-circuit grating; and the distance between metal dots between two adjacent reflecting grids is more than or equal to the minimum distance between the two adjacent reflecting grids in the resonator. The SAW resonator has the beneficial effects that on the basis of arranging the function weighted metal dot arrays on the first short-circuit grating and the second short-circuit grating, the reflection pore diameter is enlarged, so that the problem that the reflection pore diameter is too small so that the diffraction is serious and the reflection precision is influenced is solved; and the weighting of the metal dot arrays is more accurate, the sidelobe suppression is further realized, and the frequency responding performance of the SAW resonator is improved.

The invention discloses a carbon nano-onion film-based supercapacitor used in the field of AC line filtering. The electrode material of a carbon nano-onion film with an interconnected structure is synthesized on the surface of a nickel sheet by using a chemical vapor deposition method, and the electrode material of the carbon nano-onion film is synthesized by using an aqueous or organic A carbon nano-onion film-based supercapacitor assembled with two electrolytes for AC line filtering. The carbon nano-onion film-based supercapacitor can take advantage of the high curvature of the carbon nano-onion and give full play to its excellent frequency response performance and high rate performance. Moreover, it has high volume specific capacity, volume energy density and good working stability.

The invention discloses a structure for improving the output displacement and natural frequency of a piezoelectric flexible mechanism, which includes a diamond-shaped flexible mechanism, a piezoelectric stack, a piezoelectric sheet, a displacement sensor, a data acquisition system, a power amplifier and a controller, and the displacement sensor is arranged on On the rigid output end, a plurality of piezoelectric sheets are respectively fixed at both ends of the flexible beam, the signal output end of the displacement sensor is connected to the signal input end of the data acquisition system, and the signal output end of the data acquisition system is connected to the signal input end of the controller The signal output of the controller is amplified by the power amplifier and then connected to the drive signal input end of the piezoelectric stack / piezoelectric sheet. The present invention generates additional bending moments by pasting piezoelectric sheets, so that the output displacement of the diamond-shaped flexible mechanism is increased without reducing the natural frequency of the flexible mechanism; in addition, thicker flexible beams and flexible hinges can be designed to increase the natural frequency of the flexible mechanism , thus the loss of displacement amplification is compensated by the bending moment provided by the additional piezoelectric sheet.

The invention relates to the field of electric power technology, in particular to an active-passive frequency response switching control method, in particular to a frequency response control method under a large power loss fault. The present invention includes: for a two-area power grid, use solid straight lines to represent inter-area contact lines, dotted lines to represent communication lines, area A is a disturbance area, and area B is a non-disturbance area: first, establish a unit thermal power unit mathematical model, second, Establish a mathematical model of the interconnected grid. The invention realizes the transformation of frequency response from decentralized autonomous control to centralized coordinated control, from feedback control to feedforward control, and from correction control to preventive control, and can improve the overall frequency response capability of the system without increasing frequency response facilities. In this way, the frequency stability resistance capability under large disturbances is improved. Effectively intercept the frequency drop during the frequency drop stage under large disturbances to avoid low-frequency load shedding of the system, and restore the system to stability as soon as possible during the frequency recovery stage to avoid frequency oscillation during the active control process of the system.

The invention relates to the field of electric power technology, in particular to an active and passive frequency response composite control method, in particular to a frequency response control method under large disturbances. The invention includes the following steps: firstly, establishing a mathematical model of a unit thermal power unit; secondly, establishing a mathematical model of an interconnected power grid. The invention realizes the transformation of frequency response from decentralized control to centralized control, from feedback control to feedforward control, and from correction control to preventive control, and can improve the overall frequency response capability of the system without increasing frequency response facilities, thereby improving Frequency stability and resistance to large disturbances. It can also coordinate global and local control objectives, which can not only avoid low-frequency load shedding of the system under large disturbances, but also quickly restore stability to the system and avoid frequency oscillations in the active control process of the system.

In general, in one aspect, the invention features a method for driving a droplet ejection device having an actuator, including applying a multipulse waveform that includes two or more drive pulses to the actuator to cause the droplet ejection device to eject a single droplet of a fluid, wherein a frequency of the drive pulses is greater than a natural frequency, fj, of the droplet ejection device.

The invention discloses a power system AGC optimization control method including DFIG. The DFIG is taken as a negative load into each control area of ​​the power system AGC. The DFIG includes a droop control link and a speed controller; the output of the droop control link is obtained respectively Respond to the output power of the speed controller, and calculate the total active power that DFIG needs to output; establish an objective function, use the PSO-GSA algorithm to solve the objective function, and obtain the fitness value of the PSO-GSA algorithm; judge whether the end condition is met, and if so, then At the end of the optimization process, the optimal solution of the parameters to be optimized is obtained; the optimal solution of the parameters to be optimized is given to the power system AGC, and by responding to changes in the frequency of the power system, DFIG participates in the secondary frequency regulation of the power system AGC. The invention can improve the frequency modulation pressure of the traditional synchronous generator, optimize the AGC control, improve the dynamic response performance of the power system, and improve the stability of the power system.

The invention discloses a full-wind-speed frequency response control method for a doubly-fed wind generator. According to the method, frequency response control can be conducted by actively identifying wind speed intervals and modifying a drooping coefficient in a self-adaptive mode. Firstly, the relation between the load shedding rate and the suboptimum tip speed ratio of the doubly-fed wind generator is established according to a doubly-fed wind power unit characteristic curve given by a manufacturer; a full wind speed is divided into a first wind speed interval, a second wind speed interval, a third wind speed interval and a fourth wind speed interval according to the wind speed from low to high; the division criterion of the four wind speed intervals is updated online according to the current load shedding rate of the doubly-fed wind generator; when the real-time frequency of a system is lowered and exceeds a set dead zone threshold, the wind speed intervals are identified according to collected real-time wind speed signals; real-time unit spare capacity is calculated, the drooping coefficient is modified in the self-adaptive mode, and then frequency response control is completed. By means of the method, the frequency response capability of the medium-wind-speed interval and the high-wind-speed interval can be improved, and the rotating speed of the generator in the weak-wind interval and the low-wind-speed interval can be not lower than the minimum allowed rotating speed.

The invention discloses a wide-range high-precision high dynamic response eddy current displacement sensor and an implementation method. The sensor comprises an AC resonance boosting bridge, a fixed amplitude circuit, an amplitude compensating and adding circuit, an orthogonal sampling trigger signal generation circuit and a high speed sampling processor. The method comprises following steps: performing dual-path data sampling through a dual-path sampling method and calculating loss resistance of the resonance circuit according to the dual-path sampling data (S1, S2); calculating coil displacement according to the circuit loss; calculating displacement temperature drift after temperature compensation according to temperature S3. According to the invention, the sensitivity and measurement range of the sensor are increased by coil boosting, fixed amplitude excitation, and amplitude compensating; external disturbance is reduced and dynamic response and stability are increased by orthogonal sampling and digital processing.