49results about How to "Oscillation amplitude is small" patented technology

With regard to the problem of frequency response and power allocation unreasonableness during the transient process caused by parameter design unreasonableness of a parallel running virtual synchronous power generator in a micro power grid, the invention proposes an inertia damping matching mechanism of a multi-machine parallel virtual synchronous power generator (VSG). The power allocation is controlled, and meanwhile, stable transient transition (relatively low oscillation amplitude and period) of power generators running in parallel and having different capacities is ensured. A PI regulator-based improved damping control method is creatively proposed. All VSGs can work with the same damping coefficient value under a modification method, so that calculation is reduced. In VSG parallel running, the selection of inertia and damping coefficient shall consider the dynamic characteristics of a system frequency and parallel power of the VSG, and the parameters are capacity functions of theVSG; and according to a matching principle, the steady-state and transient process can be optimized, so that stable support can be provided for a large amount of distributed power supplies connectedto the micro power grid and an intelligent power grid.

The invention provides a photovoltaic array maximum power point tracking (MPPT) controller based on a segmented model. The photovoltaic array MPPT controller is connected with a photovoltaic power generation system, so that the photovoltaic power generation system works in a maximum power output state; the photovoltaic power generation system comprises a photovoltaic array, a voltage and current measurement circuit and a direct current/direct current (DC/DC) conversion circuit; the photovoltaic array MPPT controller comprises a digital signal processor/micro control unit (DSP/MCU) controller and a control module based on the segmented model, wherein the DSP/MCU controller is connected with the voltage and current measurement circuit and the DC/DC conversion circuit; and the control module based on the segmented model runs on the DSP/MCU controller. In addition, the invention also provides a photovoltaic array MPPT controlling method based on the MPPT controller and the segmented model. Through the controller and the method, the working point of the photovoltaic array is accurately converged at a global maximum value, so that optimal control is realized.

The invention belongs to the technical field of computer systems, and discloses a signal injection-based PMSM stator winding temperature online detection method. The method comprises the steps of establishing a high-performance PMSM stator temperature online calculation method, and adding an optimal signal injection strategy into the online calculation method; adding vector control on the basis ofan existing signal injection method to form a new signal injection method; performing direct current component extraction in the new signal injection method; and calculating the stator resistance andthe estimated temperature and obtaining the real-time temperature observed data. The temperature of the stator winding of a permanent magnet synchronous motor is estimated online, so that the healthcondition of the motor can be monitored, and over-temperature generation can be prevented, and the methods can also be used in motor optimization control such as active heat management and the like, and is beneficial to improving the performance of an electric driving system.

The invention discloses a method and system for suppressing the subsynchronous oscillation of a thermal power unit. The method comprises a step of establishing a suppression controller including a static var generator (SVC) and an supplementary excitation damping controller (SEDC). The two controllers have a sum relationship in the aspect of subsynchronous oscillation suppression. The SVC has a good suppression capability, and the SEDC has low investment. On the one hand, the combination of the two controllers can reduce the capacity of the SVC and reduce the investment. On the other hand, theSEDC can be used when the SVC is overhauled. The method and system can decrease, when the subsynchronous oscillation occurs, the oscillation amplitude and delay the generator tripping protection actuation time, so that workers can take more time to adjust the operation mode of the system to eliminate the subsynchronous oscillation of the unit.

The invention provides an electric power system stabilizer parameter optimization method based on a generalized phase compensation method, and the method comprises the steps: firstly, constructing a DFIG model of a double-fed wind generating set; secondly, adding the DFIG model into a power system, adding a power system stabilizer into the power system according to low-frequency oscillation existing in the power system, and optimizing parameters of the power system stabilizer by using a generalized phase compensation method; and finally, through adoption of a characteristic root analysis method and a time domain simulation method, analyzing the influence of the power system stabilizer after parameter optimization on the damping characteristic of the power system. According to the method, the PSS is optimized through adoption of the generalized phase compensation method, so that the damping characteristic of the power system after wind power grid connection can be better improved, the oscillation amplitude of the power system is reduced, the oscillation time is shortened, and the stability of the power system is facilitated; and for different operation conditions, the optimized PSShas better robustness.

The invention relates to a time-shared stabilized control method of a hall electric propulsion discharging current. On the basis of a time-shared control strategy, a relatively stable anode throttler temperature is used as a closed-loop feedback parameter at an initial ignition stage, so that failed ignition caused by using a high-oscillation discharging current as a feedback parameter directly can be avoided. After successful ignition, the discharging current oscillation amplitude is reduced; and then the discharging current is used as the closed-loop feedback parameter directly, thereby realizing stable control of the discharging current of the hall electric propulsion system, suppressing the low-frequency oscillator of the discharging current, and improving the efficiency. According to the time-shared control strategy, ignition reliability of the hall electric propulsion system at the initial ignition stage is guaranteed and the working performance of the hall electric propulsion system during the operating process is also improved.

The invention relates to the technical field of optimization of the wavelet neural network, in particular to a wavelet neural network weight initialization method based on Bayes estimation, and the state estimation and search idea is adopted in the wavelet neural network weight initialization method. The wavelet neural network weight initialization method based on Bayes estimation comprises the steps of building a wavelet neural network model, unitizing weights, inputting and optimizing wavelet nerve cell weights, and optimizing weights of nerve cells of an output layer. Wavelet neural network weight parameters are linked with the network structure, wavelet types, input data and output target values, the state estimation idea and theory are introduced into initial setting of the weight parameters, wavelet network learning and training capacity is enhanced, the wavelet network has certain pertinence in the initialization phase, and therefore the adaptability of the weights in follow-up network learning and training is improved. Compared with a traditional weight initialization method, the learning efficiency can be effectively improved, oscillation amplitude of network output can be reduced, the rate of algorithm convergence is improved, and network output divergence caused by improper weights can be avoided.

The invention discloses a method for realizing nuclear reactor load tracking. The method uses two groups of relatively-independent control rods for reactive and axial power shift power control of a nuclear reactor; the two groups of relatively-independent control rods are a T rod group and a K rod group respectively, wherein the K rod group consists of a plurality of beams of black rods; the T rodgroup comprises a plurality of beams of grey rods and black rods; during the base load operation of the nuclear reactor, only the K rod group is inserted into a reactor core, and the insertion depthof K rod group is greater than or equal to the bite amount plus 24 steps; during the load tracking operation of the nuclear reactor, both the T rod group and the K rod group are inserted in the reactor core. The method disclosed by the invention has the benefits that only one group of control rods is required to be inserted into the reactor core during the base load operation, and the defects thatthe fuel consumption is non-uniform, the control rod fluence is increased, the control rod absorption body fuel consumption is more, the control rod drive mechanism load is increased, and the like due to the insertion of the more control rods into the reactor core during the base load operation are overcome.

The invention provides an alternating current channel transmission capacity optimization method and device in an alternating current/direct current hybrid power system. The method comprises the stepsthat double-machine equivalence is carried out on a transmission-side alternating current system according to the dynamic response curve of an alternating current/direct current hybrid power grid, soas to acquire a leading generator group and a hysteresis generator group; Thevenin equivalence is carried out on the alternating current/direct current hybrid power grid from the direct current side according to the leading generator group and the hysteresis generator group; and finally the operation mode of the alternating current/direct current hybrid power grid is adjusted according to the Thevenin equivalence result of the alternating current/direct current hybrid power grid; and the alternating current channel transmission capacity is optimized in the direct current hybrid power grid. According to the invention, the problem that an alternating current channel is impacted by the collapse of the transmission power of a direct current transmission system during a recovery process and thevoltage drop of a direct current conversion bus after the generator group oscillating aroused by certain faults in the transmission-side alternating current system is solved; and reference is provided for a power grid operator to arrange the operation mode of the alternating current/direct current hybrid power grid reasonably to ensure safe and stable operation of the alternating current/direct current hybrid power grid.

The invention discloses a maglev train, a levitation control system and a method for improving operation stability, and relates to the field of levitation control. In order to avoid the influence of track irregularity interference on the levitation control stability of the maglev train, after an irregularity interference estimated value is obtained, feed-forward control is used for applying dynamic compensation to the track irregularity, so that the adverse influence of the irregularity interference on the levitation control stability can be greatly weakened, the maintenance period of the track is prolonged, the operation cost is reduced, and the operation stability and comfort of the maglev train are further improved. By adding feedforward control, the anti-interference capability of the levitation control system of the maglev train is improved, the robustness and environmental adaptability of the levitation control system are improved, and the used feedforward control and feedback control policy can also be migrated and used for other similar scenes.

The invention discloses a multi-terminal flexible direct-current power transmission control parameter optimization design method. The method comprises the steps of building a small signal model of a flexible direct-current power transmission system, wherein the small signal model comprises a main system model and a control system model; and establishing an optimal control parameter design problemtaking the characteristic value as a target function, and solving the optimal control parameter design problem taking the characteristic value as the target function by adopting an optimization algorithm based on sensitivity analysis to obtain an optimal control parameter. According to the method, the step length of each iteration can be determined through backtracking line search, iterative oscillation is prevented, and the convergence speed is increased; since the search direction and the step length are determined according to the sensitivity of the control parameters, the result of each iteration can monotonously approach the optimal solution in the optimization process, thereby improving the stability of the system.

The invention discloses a novel method for adjusting the time difference reaction of the mammal, relating to a novel protein Magedl for adjusting the circadian rhythm and the mammal, wherein the novel protein Magedl plays an important part in maintaining the normal biological clock function. In a mouse with the Magedl, the core biological clock molecular amplitude of the mouse is changed to be small, the day-night cycle of the mouse is changed to be short, and the adjusting speed in the simulative time difference reaction is accelerated. Therefore, the Magedl can be taken as a drug target for curing the time difference reaction of human body.

The present invention relates to a method for calculating or estimating at least one medical value based on several input values using artificial intelligence.

The invention discloses a seedling identification system and method of a soil-hardening salination soil seed bank, and belongs to the technical field of identification of the soil seed bank. The identification system comprises a time control module, a temperature control module, a central control module, an immersion module, a rinsing module, a seedling culturing module and a species quantity identification module. The problem that severe soil hardening influences germination of seedlings in the prior art is solved via the immersion module, the rinsing module and the seedling culturing module,and a more accurate identification method is provided for research on the soil-hardening salination soil seed bank; the species quantity identification module plants screened seeds in the appropriatesoil environment directly; and the types and quantity of species separated by the method are both exceed those of a traditional manual sorting method respectively, and it is shown that the precisionand efficiency are both higher than those of the traditional method respectively.

The invention belongs to the technical field of medicine preparation and discloses a system and method for controlling equipment parameters in a streptonigrin compound extraction process. The controlsystem comprises a power supply module, a temperature detection module, a humidity detection module, a camera module, a main control module, a cleaning module, a cloning module, a deactivation module,a fermentation module and a display module. The control method is also disclosed at the same time. According to the method, the cleaning module is used for analyzing the first cleaning effect on twoparts of target articles to judge the first cleaning efficiency and the cleaning degree of the two parts of the target articles, and then a second cleaning scheme is formulated according to the cleaning degree of the two parts of the target articles in order to achieve high-efficiency cleaning of the target articles. Texture analysis is conducted on images under a complex background, more accuratecharacteristic information can be provided, and the quality of a prepared streptonigrin compound is improved.

The invention provides a kitchen garbage truck box and a garbage truck, and relates to the technical field of garbage trucks. The kitchen garbage truck box comprises a cuboid truck box body, wherein a liquid storage cavity is formed in the truck box body, a pouring opening communicating with the liquid storage cavity is formed in the side wall of the truck box body, a plurality of baffles are arranged in the liquid storage cavity at intervals, and cavities formed between any two baffles communicate with each other; the baffle plates are fixed on the truck body. According to the kitchen garbage truck box, liquid garbage can be placed in the truck box, bumping of the liquid garbage in the transportation process is reduced, the transportation capacity is large, and the transportation efficiency is high. In addition, the invention further provides a garbage truck. The garbage truck comprises the kitchen garbage truck box, and therefore the liquid garbage can be transported conveniently.