10results about How to "Avoid frequency" patented technology

A method for synchronous excitation of multiple exciters relates to the field of dynamic testing and vibration control technology for large civil structures. The method includes the following steps: after constructing a unified time reference based on satellite navigation signals and a rubidium atomic clock, excitation amplitude and phase parameters are obtained based on the target modal requirements, and these parameters are sent to all exciter slave stations; the exciter slave stations generate a reference trajectory based on the excitation amplitude and phase parameters, enabling the exciter motor shaft angle to follow the reference trajectory in real time and output the target excitation; the phase error is obtained based on the measured excitation phase value and the reference trajectory, and then the motor angular velocity of the exciter is corrected based on the phase error. This invention solves the problems of startup phase error and long-term frequency drift in master-slave triggering schemes, ensuring synchronous start-up of all exciters. Combined with dynamic correction of the exciter motor angular velocity, it suppresses phase drift during long-term operation, significantly improving the excitation efficiency of higher-order modes and the clarity of the response signal.

The application discloses a kind of secondary frequency control method, device and storage medium based on neural network, belong to microgrid control technical field, method includes: obtaining the rated angular frequency of distributed microgrid preset, and the active power of each distributed power generation unit;Active power is respectively input into the corresponding pre-trained neural network, and the frequency compensation of each distributed power generation unit is output, the frequency deviation caused by droop control is compensated, so that the angular frequency of distributed microgrid output recovers to the rated angular frequency preset;Corresponding pre-trained neural network refers to the neural network that each distributed power generation unit corresponds one training process and is added privacy protection processing, so that attacker cannot infer whether single sample is used for the training of neural network according to neural network output result.The application can improve the security and stability of microgrid, solve the problem that traditional secondary frequency control method exists privacy leakage risk and security risk.

This invention discloses a method for suppressing current imbalance and power oscillations based on a virtual synchronous generator (VSG). First, a traditional VSG loop model is established and its parameters are tuned. Then, the positive and negative sequence components of the grid-connected voltage, filter capacitor terminal voltage, and grid-connected current are extracted using a time-delay cancellation method and transformed to a synchronous rotating coordinate system. An equivalent VSG grid-connected loop model is added to the traditional VSG model. The traditional active power and extended reactive power calculation methods are transformed to the synchronous rotating coordinate system, and a reference value for the grid-connected current that suppresses the second harmonic component of the power is derived. A PI controller is used to make the actual grid-connected current track the reference value, and the output modulated wave drives the inverter. This invention can simultaneously suppress the second harmonic oscillations of active and reactive power, improve grid-connected current imbalance and distortion problems, while retaining the active power frequency regulation, reactive power voltage regulation, and inertial support characteristics of the VSG, thus improving the stability and power quality of the new energy grid-connected system.

The application relates to the technical field of micro-grid energy management, and discloses a micro-grid dynamic coordination control method for distributed energy. The method acquires a data set of multiple monitoring nodes of a micro-grid in a historical operation interval; performs multi-resolution fluctuation analysis on an energy output data set, an energy demand data set and a system frequency data set to generate an output fluctuation index, a demand fluctuation index and a frequency fluctuation index; takes the fluctuation index as a guide variable, adopts a group optimization algorithm to explore in a micro-grid control parameter space, and locates an optimal control interval; periodically adjusts distributed power generation units and load units in the micro-grid according to the optimal control interval, generates a regulation and control instruction set and executes the regulation and control instruction set to achieve dynamic coordination control. The application realizes accurate interval positioning and efficient coordinated operation of micro-grid control, and effectively improves the stability and regulation and control efficiency of a distributed energy system.

The invention belongs to the field of micro-grid control, and discloses a distributed direct current micro-grid secondary control method based on preset time, which comprises the following steps: acquiring a node operation original sequence in a periodic acquisition and time sequence storage mode, analyzing a state feature vector and constructing a node state set; analyzing to obtain a primary droop feature set and a primary operation deviation set; constructing a time constraint error evolution path and determining a preset time error sequence; based on the preset time error sequence and in combination with a neighborhood communication mechanism, generating a distributed secondary regulation quantity; and generating a secondary control instruction based on the distributed secondary regulation quantity in combination with sequence updating, saturation limitation and a soft start mechanism. Through a distributed sequential control means based on predetermined voltage recovery and frequency coordination, the frequency consistency of a plurality of micro-grid systems can be maintained, and significant frequency fluctuation and drift caused by load fluctuation or power supply input abrupt change can be effectively avoided.

The invention relates to the technical field of nano material preparation, and discloses a high-dispersion zinc oxide preparation method based on high-speed shearing, which comprises the following steps: mixing 4.1829-32.7715 g of a zinc source precursor, 100 m l of an organic solvent and 0-1 m l of laboratory self-made ultrapure water, and carrying out high-speed shearing at 50-70 DEG C for 5-30 minutes; maintaining the temperature and shearing, quickly adding 10-50ml of alkali liquor, and reacting for 5-30 minutes; maintaining the temperature and shearing, quickly adding 2-20m l of laboratory self-made ultrapure water, and reacting for 5-30 minutes; and standing, centrifugally washing and drying the product. According to the preparation method disclosed by the invention, micro-mixing is enhanced through full-process high-strength shearing, explosive nucleation is induced, soft agglomeration among particles can be destroyed by continuous shearing force, and particle growth is inhibited, so that zinc oxide with small particle size and high dispersity is prepared.

The invention belongs to the technical field of power supply dispatching, and particularly relates to an intelligent regulation and control method for UPS centralized power supply for an underground alternating current charging pile, which comprises the following steps: acquiring vehicle charge state and travel end point information, and calculating theoretical residual electric quantity; candidate charging parking spaces are screened along the driving path, the UPS releasable power and the load rate are obtained, and environment data, the bus voltage distortion rate and the load level are collected; calculating the charging duration and the charging quantity, screening the charging piles which meet the constraint conditions and are safe in environment, and determining a target charging pile; performing charging power prediction in combination with the input power of a vehicle charger, determining an inversion module scheduling strategy and bus parameters according to the available capacity and redundancy capacity of the UPS, and forming a pre-scheduling scheme; when the vehicle approaches, the inversion module is started, parallel operation synchronization is completed, and a pre-output power supply state is formed; after the vehicle is connected, BMS feedback is obtained and matched with the preset scheme for judgment, charging is executed when conditions are met, otherwise, the charging is executed after adjustment, and therefore the power supply stability and the charging efficiency are improved.

The invention belongs to the technical field of distributed optical fiber sensing, and discloses a Brillouin dynamic grating reflection spectrum measuring device based on spectrum demodulation, which comprises a pump light source and a tunable laser, the pump light source is connected with the optical fiber coupler, a first output port and a second output port of the optical fiber coupler are respectively connected with input ports of the single side band modulator and the second polarizer, and an output port of the single side band modulator is connected with one end of the polarization maintaining optical fiber through the first polarizer; the output port of the second polarizer is connected with the first input port of the polarization beam splitter; an output port of the tunable laser is connected with a second input port of the polarization beam splitter through the third polarizer and the optical circulator, and a combined beam output port of the polarization beam splitter is connected with the other end of the polarization maintaining optical fiber; and a reflection port of the optical circulator is connected with an input port of the spectrograph. According to the invention, rapid, high-precision and low-cost measurement of the BDG reflectance spectrum is realized, and the method is especially suitable for dynamic distributed optical fiber sensing.

A method, system, product, and medium for coordinated control of distributed power sources are disclosed. The method includes: real-time detection of the power output decline rate of photovoltaic power plants and wind turbines, current grid load data, power demand, and the remaining capacity and discharge power of energy storage batteries; under high-risk conditions, calculating the real-time load characteristics of each load and prioritizing all loads; isolating non-critical loads ranked in the priority order within a preset low percentage range from the main grid and issuing isolation notifications to their load sides; when insufficient power is detected, injecting electrical energy into the grid by controlling the power supply or discharge status of controllable loads; calculating the current power gap, and controlling the start-up of inactive generator units when the power gap exceeds a preset threshold. Implementing the technical solution provided in this application improves the dynamic response capability of the power grid under distributed power fluctuations and load surges.

The application provides a micro-grid grid-connected and off-grid control system, through constructing a gated loop unit timing prediction model, accurately predicting net load and power distribution network demand in multiple time periods in the future, and simultaneously minimizing power purchase and sale cost, line loss and power supply power shortage by using an improved NSGA-II multi-objective optimization algorithm, so that the economic efficiency and reliability are cooperatively optimized; a hierarchical architecture combining a regional coordination control layer and a micro-grid local control layer is used, so that the global optimization and dynamic response performance are considered; N-1 safety check and virtual synchronous machine pre-synchronization control are introduced, so that the problems of voltage out-of-limit and frequency instability caused by grid-connected and off-grid operation are effectively avoided; through a digital twin three-dimensional dynamic display module, power flow and switch state are directly presented, so that the situation awareness ability of operation and maintenance personnel to complex micro-grid groups is significantly improved; meanwhile, an incremental learning mechanism is used to continuously update the prediction model, so that the system can adapt to long-term changes of load and power generation.