45results about How to "Meet engineering needs" patented technology

The invention relates to a method for calculating the anti-overturning bearing capacity of an electric pole with an assembly type foundation, and belongs to the technical field of power grid operation and maintenance, and the method comprises the steps: 1, obtaining the data of an electric pole body, and calculating the anti-overturning ultimate bearing capacity F1 of the electric pole body; 2, data of the fabricated foundation are obtained, and the anti-overturning ultimate bearing capacity F2 of the fabricated foundation is calculated; and 3, according to the F1, the F2 and the interaction coefficients corresponding to the F1 and the F2, the overall anti-overturning ultimate bearing capacity F of the electric pole body and the assembly type foundation is calculated. Scientific reference is provided for the electric pole with the assembly type foundation, and design of the electric pole with the assembly type foundation can be assisted.

The invention relates to the field of building materials, in particular to a fiber-reinforced mortar material and a preparation system thereof.The mortar material comprises, by weight, 1 part of cement, 3 parts of gravel, 0.65 part of tap water and 0.01-0.03 part of fiber, the gravel comprises natural sand and reclaimed sand, and the proportion of the reclaimed sand in the gravel is 30%, 60% or 100%. According to the scheme, for the performance and application of reclaimed sand in cement mortar after natural sand is replaced, systematic research is given, different material proportions can be set according to different engineering requirements by referring to the research result of the scheme, mortar materials suitable for different projects can be produced, and the production cost of the mortar materials can be reduced.

The invention relates to a super-early-strength ultra-high-performance potassium magnesium phosphate cement-based composite material and a preparation method thereof.The super-early-strength ultra-high-performance potassium magnesium phosphate cement-based composite material (UHPMKPCC) takes dead burned magnesium oxide and monopotassium phosphate as cement raw materials, takes silica fume as one of cementing materials, and takes calcium carbonate as one of the cementing materials; wollastonite powder, metakaolin, fly ash, sodium dihydrogen phosphate and the like are used as auxiliary cementing materials, quartz sand is used as aggregate, and a composite retarder and a water reducing agent are adopted to jointly realize preparation and application of the UHPMKPCC with the ultra-low water-binder ratio. Compared with the existing ultra-high performance Portland cement-based material (UHPC) technology, the UHPMKPCC disclosed by the invention has the advantages of remarkable ultra-early strength mechanical property, low drying shrinkage and the like; compared with an existing ultrahigh-performance magnesium ammonium phosphate cement-based material technology, the UHPMKPCC has the advantages that the setting time can be effectively regulated and controlled, and no ammonia gas is released. The method can be applied to safe solidification treatment of radioactive nuclear waste in the fields of first-aid repair, rush building and reinforcement in the civil engineering field and safe treatment of nuclear waste.

The invention provides a mortar compressive strength prediction model construction method based on a low-field magnetic resonance relaxation technology. The method comprises the following steps: 1, preparing a standard mortar test piece, and carrying out maintenance and water saturation treatment; 2, carrying out low-field magnetic resonance relaxation test analysis on the standard mortar test piece; 3, testing the compressive strength of the standard mortar test piece; 4, determining a relation model of the standard mortar test piece and the pore structure; according to the mortar compressive strength prediction method based on the low-field magnetic resonance relaxation technology, firstly, low-field magnetic resonance relaxation test analysis is performed on a to-be-tested mortar test piece, and then the compressive strength of the to-be-tested mortar test piece is predicted through a compressive strength prediction model obtained through the mortar compressive strength prediction model construction method based on the low-field magnetic resonance relaxation technology. The mortar compressive strength prediction model based on the low-field magnetic resonance relaxation technology is high in applicability and good in stability, and the mortar compressive strength prediction method based on the low-field magnetic resonance relaxation technology minimizes damage to buildings while accurately predicting the mortar compressive strength.

The utility model provides a portable gas detection instrument belongs to gas detection technical field, include: external probe, semiconductor type sensor and catalytic combustion type sensor, semiconductor type sensor and catalytic combustion type sensor are installed in the inside of external probe simultaneously, external probe is designed with convenient replacement interface, is convenient to replace, the appearance of external probe adopts cylinder or oval, installs two gas sensors and temperature sensor, semiconductor sensor works in the lower state of gas concentration, and catalytic combustion sensor works in the higher state of gas concentration, realizes complementary advantages, and the signal of gas sensor is temperature compensated to obtain more accurate detection data, and the current temperature can also be displayed simultaneously by the detection instrument, the characteristics of sensor probe miniaturization are reserved, and the probe is convenient to replace, is convenient in narrow space application, has no influence to the structure of gas detection instrument itself, and is convenient for production reform.

The invention provides an epoxy modified cement-based material, the epoxy modified cement-based material comprises an organic phase structure and inorganic crystals, and the inorganic crystals are radially distributed on the surface of the organic phase structure; the organic phase structure is a spherical or sphere-like structure with the diameter of 3-15 microns; the inorganic crystal is of a needle-shaped, rod-shaped or sheet-shaped structure with the length being 0.3-3 microns and the diameter being 0.05-0.5 microns. The epoxy modified cement-based material disclosed by the invention shows good adhesion and dispersion resistance under water or in a humid environment, can realize rapid underwater construction, and keeps stable performance for a long time under harsh conditions such as a marine environment and a humid environment; the engineering requirements of multiple fields such as building structure repairing, underwater repairing, rapid first-aid repair, ocean protection and road and bridge engineering are met, and the integration of high strength, high toughness, strong interface bonding and long-acting durability is realized.

The invention relates to the technical field of geotechnical engineering, and particularly discloses a granite weathered soil 3D particle morphology quantitative characterization technology which comprises a three-dimensional scanning subsystem, an intelligent image processing subsystem, a morphological parameter calculation subsystem, a data mining and machine learning subsystem, a virtual simulation and optimization design subsystem and a user interaction interface subsystem. The three-dimensional scanning subsystem is used for acquiring three-dimensional form information of granite weathered soil particles by using a high-precision three-dimensional scanning technology; according to the technology for quantitatively characterizing the 3D particle morphology of the granite weathered soil body, the particle morphology can be presented in a high-precision mode, researchers can observe and analyze the fine structures and characteristics of the particles more intuitively, the behaviors of the particles in a complex environment can be accurately predicted, and the analysis accuracy of the particles is improved. Reliable reference basis is provided for engineering application, potential risks can be evaluated in advance, and corresponding countermeasures can be formulated.

The application discloses a Transformer oil well production prediction method and device based on gating constraints and Kalman filtering, and a medium, which comprises the following steps: first, obtaining oil well historical production data and preprocessing; then, using a mutual information method to screen input features related to target production, and constructing conditional gating constraint features representing the opening and closing states of the oil well; then, inputting the processed time sequence samples into a Transformer prediction model to obtain initial prediction results of the oil well production; then, performing state constraint on the initial prediction results according to the conditional gating constraint features, and performing causal recursive residual correction on the prediction results of subsequent time based on the current time prediction residual by using Kalman filtering to obtain final prediction results; further, performing grid search on Kalman filtering parameters Q and R for optimization, and determining the optimal parameter range by combining a heat map. The application can effectively reduce the prediction error, and improve the accuracy, stability and robustness of the oil well production prediction.

The invention discloses a fatigue strength reliability analysis method and system for reactor equipment and a medium, and relates to the field of reactor structural mechanics. The method is suitable for conventional fatigue analysis calculation of a reactor equipment structure, the randomness of all input parameters is introduced into calculation, uncertainty in the aspects of geometry, materials, loads and the like is involved, a complete fatigue strength reliability analysis process is established, and the reliability of the fatigue strength is improved. Obtaining the failure probability of the fatigue strength and the sensitivity of the fatigue strength to each input parameter; the transition of reactor equipment structure fatigue analysis from a determination theory to a probability theory is realized; in addition, the scheme of the invention can support the subsequent development of structure optimization related to each input parameter, and meet a series of engineering requirements.

The invention provides an impeller structure for widening the pressure ratio and flow range of a gas compressor, which is a semi-open impeller and comprises a wheel disc, a wheel shaft and blades, the wheel shaft is arranged in the middle of the wheel disc, and the blades are evenly arranged between the wheel shaft and the wheel disc with the wheel shaft as the center. The blades comprise the main blades and the auxiliary blades, the auxiliary blades are arranged between the two main blades, and the height of the main blades is larger than that of the auxiliary blades. According to the wing-shaped swept impeller, the front edge of the blade is subjected to swept-forward design, the front edge molded line is subjected to optimization design on the basis, so that the wing-shaped swept impeller is formed, the pressure ratio and the flow range of a gas compressor can be effectively widened, and the purpose of meeting engineering requirements is achieved.

This invention discloses a fast quasi-peak detector simulation method for EMI receivers based on pulse detection coefficient fitting, comprising: acquiring the amplitude result of the target signal after processing by a peak detector; establishing a quasi-peak response model and determining the pulse detection coefficients; calculating the quasi-peak detection result corresponding to the target signal using the mathematical mapping relationship between quasi-peak voltage and peak voltage; and using the quasi-peak detection result as a fast predictive output to replace the time constant integration of traditional quasi-peak detection circuits for electromagnetic interference assessment. This invention is beneficial for the electromagnetic compatibility design of power electronic equipment and solves the problems of electromagnetic compatibility array testing time and cost.

The embodiment of the invention provides a multi-heat-pump system and a control method thereof. The multi-heat-pump system comprises a first heat pump system, a second heat pump system, a shell, an inner air valve, a side air valve and an upper air valve. The inner air valve, the first heat pump system and the second heat pump system are arranged on the inner side of the shell, and the first heat pump system and the second heat pump system are connected through the inner air valve; the side air valve is arranged on the side face of the first heat pump system and the side face of the second heat pump system, and the side air valve is connected with the first heat pump system and the second heat pump system. The upper air valve is arranged above the first heat pump system, and the upper air valve is connected with the first heat pump system; the inner air valve, the side air valve and the upper air valve are used for being opened or closed in different operation modes so that the first heat pump system and the second heat pump system can conduct heat exchange. According to the embodiment of the invention, the adaptive capacity of the heat pump system can be improved, and engineering requirements are met.

The invention relates to an integrated heat dissipation structure of a low-orbit satellite phased-array antenna, and relates to the technical field of satellite heat dissipation. The integrated heat dissipation structure comprises a heat storage area, a heat conductor and an aluminum ammonia heat pipe which are arranged between a satellite body and a phased-array antenna, one end of the aluminum ammonia heat pipe is in contact with a heating device of the phased-array antenna, and the other end of the aluminum ammonia heat pipe is inserted into the heat conductor; the heat storage area is filled with a phase change material used for absorbing and storing heat, one side of the heat storage area is attached to a satellite body, and the other side of the heat storage area is attached to the heat conductor; the satellite body is further provided with a plurality of heat dissipation teeth used for dissipating heat in the heat storage area. Aiming at the characteristics that a low-orbit satellite is small in ground winding period and short in starting time, through the heat dissipation structure which comprehensively covers conduction, heat storage and radiation and is integrally designed, the heat dissipation requirement of the low-orbit satellite phased-array antenna can be better met, and the heat dissipation performance and reliability of the satellite-borne digital phased-array antenna are improved.

The invention relates to the technical field of civil engineering and prefabricated part visual inspection, in particular to a laminated slab embedded structure detection method and system and a readable medium. According to the laminated slab embedded structure detection method provided by the invention, a backbone network is improved on the basis of a YOLOv8 framework, and a new laminated slab detection model is formed so as to detect the embedded structure on the unpoured laminated slab. In a new backbone network AIEB network module, on the basis of a traditional backbone network, a multi-stage auxiliary information feature extraction operation composed of a CBLINE operation and a CBFuse calling operation is added, so that target feature information of reinforcing ribs with a small number to dozens of pixel points in a photo and target feature information of a laminated slab with the size to almost a whole photo can be well extracted; therefore, the new backbone network can extract richer image features, and more information is provided for feature fusion processing of the subsequent neck network. According to the invention, the problem of lack of an effective pre-pouring prefabricated part detection technology is solved.

The present invention relates to the technical field of closed dryer equipment, and in particular to a closed dryer and a method for calculating the dehumidification capacity thereof. The device comprises a compressor, a condenser, a throttle valve, an evaporator, a first pipe, a second pipe and a third pipe; the first pipe connects the outlet end of the compressor with the inlet end of the condenser, the second pipe connects the outlet end of the condenser with the inlet end of the evaporator, and the third pipe connects the outlet end of the evaporator with the inlet end of the compressor; the throttle valve is arranged on the second pipe; the technical solution automatically obtains multiple pressure values ​​and temperature values ​​by arranging multiple pressure detection devices and multiple temperature detection devices on the refrigerant system of the closed dryer, thereby calculating the refrigerant parameters, and then calculating the heat exchange capacity of the condenser, the compressor power, the cooling capacity, the system air volume, the sensible heat and latent heat of the evaporator, and gradually calculating the dehumidification capacity of the system.

The invention belongs to the technical field of fluid mechanical engineering, and particularly relates to a centrifugal pump and turbine dual-mode shaft power calculation method based on mechanical energy and internal energy analysis. Performing three-dimensional flow field calculation based on the pump mode system mass flow; calculating the specific mechanical energy difference between the outlet boundary and the inlet boundary of the pump mode system; calculating the specific internal energy difference between the outlet boundary and the inlet boundary; calculating pump mode shaft power of the centrifugal pump; determining a turbine mode system of the centrifugal pump; three-dimensional flow field calculation is executed based on the turbine mode system mass flow; calculating the specific mechanical energy difference between the inlet boundary and the outlet boundary of the turbine mode system; calculating the specific internal energy difference between the outlet boundary and the inlet boundary; calculating the turbine mode shaft power of the centrifugal pump; through collaborative analysis of mechanical energy and internal energy, the structure and operation characteristics of the pump and turbine dual mode of the centrifugal pump are adapted, and the technical blank of quantitative shaft power calculation under the pump and turbine dual mode of the centrifugal pump is made up from the perspective of system energy dissipation and conservation.

The application discloses a permafrost region railway track roadbed reinforcing and temperature controlling structure, method and storage medium, and the roadbed reinforcing and temperature controlling structure comprises, from top to bottom, a steel rail, a sleeper, a subgrade surface layer, a subgrade bottom layer and an embankment; a transverse ventilation pipe is arranged below the embankment; a plurality of gravel piles are arranged at the bottom of the transverse ventilation pipe; the pile body of the gravel pile is a porous structure formed by gravel filling and is communicated with the transverse ventilation pipe; the gravel pile at the soft soil foundation layer is wrapped by an economical geogrid; the gravel pile at the future maximum soft layer and the safety reserve layer is wrapped by a high-strength geogrid; and the gravel pile at the permafrost layer is not wrapped. The application adopts the composite wrapped gravel pile reinforcing structure to reinforce the foundation based on the degradation position of the permafrost, simultaneously reduces the deep soil temperature through the temperature controlling structure, maintains the stability of the permafrost layer, and improves the stability of the reinforcement.

This invention provides a modular inertia disk-type inertia torque adjustment mechanism. Through standard module units with calibrated inertia values ​​and a conical sleeve-type quick-locking mechanism, it achieves precise quantification and rapid assembly / disassembly of inertia, solving the problems of cumbersome operation, low accuracy, and poor repeatability associated with existing manual steel plate addition / reduction methods. By utilizing the target torque-angular acceleration conversion algorithm and greedy combination optimization algorithm built into the inertia matching controller, it can automatically output the optimal module configuration scheme without manual calculation, improving testing efficiency and accuracy. Furthermore, through the safety verification function of dynamic torque and motion range prediction, it can provide early warning of risks exceeding mechanical limits, avoiding equipment damage and safety hazards. This invention, while retaining the compact structure and high reliability of the original inertia disk assembly, significantly improves the intelligence level and ease of operation of inertia torque adjustment, meeting the engineering requirements of dynamic load simulation for high-precision servo mechanisms.

The invention provides a face recognition method based on point cloud data and RGB image sequential verification, and the method comprises the following steps: collecting two types of data at the same time, completing the face detection and cutting of an RGB image, combining histogram equalization and illumination compensation, extracting unitized features, comparing the unitized features with a feature library, and carrying out the confidence calibration. And according to the first upper threshold value and the first lower threshold value, primary judgment of passing, re-verification or refusal is made. After the RGB image passes verification, selecting a point cloud corresponding to a human face region, executing voxel downsampling, counting abnormal point removal and normal estimation, calculating local geometric description, performing robust registration, and constructing a single geometric similarity index based on a median absolute deviation of a point-to-surface residual error and quantile statistics; and outputting passing, re-checking or refusing according to the second upper threshold value and the second lower threshold value. Only when the two stages pass, an identity conclusion and confidence information are given; and when any stage is not passed or re-verification is not passed, outputting a rejection result or triggering a warning or auxiliary verification.

The raise boring machine comprises a base, a second fixing plate is fixedly installed on the top of the base, a motor is fixedly installed on the second fixing plate, the output end of the motor is rotationally connected with the second fixing plate, and the output end of the motor penetrates through the second fixing plate and is rotationally connected with a rotating rod; the end, away from the motor, of the rotating rod is fixedly connected with a driving gear, the driving gear is located between the two gear racks, and the driving gear is engaged with the two gear racks. Compared with the prior art, a driving gear on a rotating rod is driven by a motor to rotate, so that two gear racks meshed with the driving gear move, a clamp is driven to clamp a drill rod, and a second fixing block is connected through a connecting rod to slide in a second groove; therefore, the clamp connected with the second fixing block is supported.

This invention discloses a design method for steel fiber reinforced concrete (SFR) materials based on multiple performance requirements, comprising: acquiring raw data of SFR parameters and performance, and determining a training dataset; training an initial convolutional neural network (CNN) model based on the training dataset to obtain a CNN performance prediction model; constructing a virtual function of SFR performance as the objective function using the CNN performance prediction module; obtaining the constraints of the basic performance parameters corresponding to the objective function; optimizing the concrete mix proportion for the objective function under each constraint using a genetic algorithm, selecting the optimal solution that meets the preset performance indicators, and determining the optimal solution set; and using the TOPSIS method to select the optimal solution set to obtain the optimal design scheme for SFR materials. This invention is beneficial for improving the various performance characteristics of SFRs, avoiding raw material waste, and achieving sustainable development of building materials.

The utility model discloses an HTCC-based differential line pair inner equal-length structure. Comprising a routing of a P-end differential line on a first wiring layer, a routing of an N-end differential line on the first wiring layer, a routing of the P-end differential line on a transition layer, a routing of the N-end differential line on the transition layer, a routing of the P-end differential line on a second wiring layer, a routing of the N-end differential line on the second wiring layer, and a via hole of a differential transmission line from the first wiring layer to the transition layer, and the differential transmission line passes through a via hole, a differential transmission line input end bonding pad and a differential transmission line output end bonding pad from the transition layer to the second wiring layer. The structure provided by the utility model has three significant advantages: firstly, the space required for wiring can be greatly reduced; secondly, a transmission path is scientifically optimized, so that the signal transmission distance is effectively shortened; and finally, high quality and stability of signal transmission are powerfully ensured by means of a symmetrical and equal-length ingenious design.

The invention relates to the field of thermal management of power batteries, in particular to a method for optimizing the cooling performance of a liquid cooling plate of a power battery. The optimization method comprises the following steps: firstly, calculating an estimated value of a heat dissipation demand of the power battery pack, and determining a size range of a liquid cooling pipeline in a liquid cooling plate and a peripheral size of the liquid cooling plate; determining the topological form of the liquid cooling loop, and constructing an optimization model by taking the size parameters and topological position parameters of each section of the liquid cooling plate pipeline as variables; turbulence enhancement and heat transfer enhancement are realized by utilizing the enhanced heat transfer unit, the heat transfer efficiency of the liquid cooling pipeline is improved, and then step-by-step optimization is carried out on the liquid cooling pipeline, the arrangement mode of the enhanced heat transfer unit and the size of the enhanced heat transfer unit by adopting a multi-layer optimization method, so that the NP problem is prevented from being solved, and the solution efficiency is relatively high; and an optimization scheme meeting engineering requirements can be obtained. According to the invention, multi-objective optimization can be carried out for different performance indexes of the liquid cooling pipeline, so that the method has wide applicability.

The invention discloses a calculation method and device for the maximum temperature of a dispersion type fuel element and a verification method, and the method comprises the steps: S1, carrying out the region division of the fuel element, and forming a first region and a second region; s2, according to the probability distribution of the coated fuel particles in the first area and the second area, correcting the initial volume ratio eta of the coated fuel particles in the first area and the second area, and respectively determining the corrected volume ratio eta z of the coated fuel particles in the first area and the second area after modification; and S3, calculating the temperature tmaxr = 0 at the center of the second region according to the corrected volume ratio eta z of the coated fuel particles of the first region and the second region and the radiuses of the outer boundaries of the first region and the second region, so as to obtain the highest temperature tmax of the fuel element. According to the method and the device, the more accurate highest temperature tmax of the fuel element can be determined under the condition corresponding to the probability distribution, so that the corresponding engineering requirements are met.

This invention discloses a coupling method for aerodynamics and vehicle dynamics applicable to high-speed trains, relating to the interdisciplinary field of aerodynamics and vehicle dynamics. The method includes: establishing separate aerodynamic and vehicle dynamic models for the high-speed train; exchanging data between the two models using a dual-time-step time-progression method, improving computational time accuracy, step size, and stability. While comprehensively considering the interaction between the high-speed train and its surrounding flow field, the influence of track irregularities, and tunnel effects, a multi-region mesh generation method is adopted, improving the quality and efficiency of mesh generation. Furthermore, the overlapping mesh method avoids mesh reconstruction problems. Simultaneously, the use of six-degree-of-freedom motion velocity to reflect the attitude changes of the high-speed train simplifies the coupling steps. The entire process saves time on mesh generation, calculating the displacement of mesh nodes around the train, mesh reconstruction, and computational iterations, enabling the coupling method to be implemented quickly and on a large scale.

The present invention relates to the technical field of tailings treatment, and in particular to a vanadium-titanium tailings-based clinker-free cementitious material and a preparation method thereof. A vanadium-titanium tailings-based clinker-free cementitious material comprises the following raw materials by weight: 200-250 parts of vanadium-titanium tailings powder, 120-160 parts of titanium slag, 30-60 parts of sulfur correction materials, 50-60 parts of calcium correction materials and 1-3 parts of silicon correction materials. The present invention uses the vanadium-titanium tailings powder produced by mining as a raw material, uses the titanium slag as a modifier and adds sulfur, calcium and silicon correction materials to make the cementitious system more stable and meet the strength requirements. The solid waste materials of the present invention, such as vanadium-titanium tailings powder, titanium slag, etc., meet the needs of the project and realize the reuse of solid waste materials. At the same time, the present invention uses vanadium-titanium tailings powder and titanium slag to completely replace cement, reduce the amount of cement used, reduce engineering costs, reduce carbon emissions, and achieve green environmental protection and resource recycling.

The present invention relates to the technical field of comprehensive energy optimization configuration, and specifically discloses a comprehensive energy system optimization configuration method considering unified energy balance, including: constructing flexible load and energy supply and consumption end equipment models, calculating the energy output and energy consumption of equipment in the comprehensive energy system; introducing flexible load response cost, equipment cost, electricity transaction fee and carbon tax to construct the objective function; introducing the universal conversion method of standard coal quantity to coordinate and calculate various forms of energy supply and consumption entities in the comprehensive energy, and constructing unified constraints and balance equations for various energy forms and media in the comprehensive energy system; solving the objective function based on genetic algorithms and constraints, outputting planning results, and realizing the optimization configuration of the comprehensive energy system. The method of the present invention solves the problem of difficulty in optimizing configuration caused by the diversity of energy forms in the comprehensive energy system.

The invention discloses a method and system for predicting the maximum stress intensity of a composite material based on a wave function, and the method comprises the steps: taking the composite material as a microscopic unit continuum, and introducing the wave function to describe the microscopic interaction and stress transfer mechanism of the composite material. Utilizing finite element analysis and numerical simulation methods to construct a wave function model of an internal stress field of the composite material; carrying out stress decomposition on the isotropic material through a Helmholtz formula, carrying out expansion on the isotropic material layer by adopting a new vector form wave function, and introducing a scale factor for optimization calculation; solving the wave function to obtain stress distribution of the composite material; and according to the stress distribution, searching a stress peak region by using a mathematical optimization algorithm, and predicting the maximum stress intensity value of the composite material. The method is characterized in that behaviors of the composite material in a complex stress state can be accurately simulated through the wave function model, so that the maximum stress intensity is accurately predicted, and the research result can meet the requirements of industries and fields such as aerospace, automobile manufacturing and construction.

The invention relates to the technical field of power systems, in particular to an MMC sub-module synchronous pre-charging method based on power balance. Charging power is obtained by designing closed-loop control of sub-module capacitors on the basis of a power balance principle, then total power released by an alternating current side or a direct current side is calculated through power conservation and charging current feedback control, synchronous charging of capacitor voltages of upper and lower bridge arm sub-modules is completed, power difference is introduced, and synchronous charging of the capacitor voltages of the upper and lower bridge arm sub-modules is completed. And voltage sharing of the sub-modules in the bridge arms and voltage sharing between the bridge arms are realized. The method can be applied to alternating-current side and direct-current side charging, and due to the fact that synchronous charging of the upper bridge arm sub-module and the lower bridge arm sub-module is achieved, the pre-charging speed is remarkably increased. In addition, the same voltage and current double-closed-loop control is adopted in the pre-charging state and the normal state of the MMC, so that the starting time can be obviously shortened. According to the invention, a novel control strategy is provided for the pre-charging of the MMC sub-module, and the method has certain significance in reducing the speed increase of fault restart and normal start in high-voltage direct-current power transmission.

The invention belongs to the technical field of aircraft engine hanging structure modeling, and particularly relates to an aircraft engine hanging connection structure modeling method which comprises the steps that 1, finite element models of a front hanging connector, a rear hanging connector, a left pull rod, a left pull rod connector, a right pull rod and a right pull rod connector are established and assembled into a hanging structure finite element model; 2, establishing an engine simplified model according to force transmission analysis; 3, accessing the engine simplified model to the finite element model of the hanging structure; and 4, accessing the finite element model of the hanging structure to the finite element model of the machine body.