1200 results about "Electromagnetic compatibility" patented technology

The invention discloses a metasurface array antenna housing, belongs to the technical field of electromagnetic wave regulation and control, and solves the problem of how to improve the transmittance and absorptivity of a metasurface to electromagnetic waves. Electromagnetic waves with different frequencies resonate on the first metasurface wave-absorbing layer and the second metasurface wave-absorbing layer respectively, so that the electromagnetic waves are absorbed by the lumped resistor. And the metasurface wave-transmitting layer re-radiates electromagnetic waves of a communication frequency band to enable the electromagnetic waves to penetrate through the metasurface unit, and meanwhile, the surface of the metasurface wave-transmitting layer can serve as a metal floor of the first metasurface wave-absorbing layer and the second metasurface wave-absorbing layer due to copper coating. The antenna can be widely used in the scenes of radar stealth, communication antenna integration, electromagnetic compatibility, wireless energy transmission and the like, and has a good application prospect.

The invention relates to a satellite cabin load layout optimization method based on a quantum algorithm, and the method comprises the following steps: listing a mathematical expression form of an optimization target and a limiting condition according to a satellite cabin load layout requirement, and generating a constraint optimization problem model; wherein the optimization target and the limiting condition at least comprise a satellite quality characteristic requirement, a space geometric compatibility requirement, a thermal control requirement, an electromagnetic compatibility requirement, an installation and maintenance requirement and an installation position requirement of special instrument equipment; converting the layout constraint optimization problem mathematical model into an optimization objective function in a secondary unconstrained binary optimization form; solving the optimization objective function by using a quantum optimization algorithm to obtain an optimization vector; and calculating the load position and attitude of the satellite cabin by optimizing the vector, and carrying out inversion to obtain a final satellite cabin load layout scheme. According to the method, the non-deterministic polynomial problem of satellite cabin load layout optimization can be solved in an accelerated manner by utilizing the characteristics of superposition, entanglement, interference and the like of quantum bits, and a new technical approach is provided for improving the design efficiency of a satellite cabin load layout optimization scheme.

The invention discloses an ordered charging management and control terminal and method for a charging robot, and relates to the technical field of robot charging management and control, and the method comprises the following steps: S1, installing an electric power data collection device at each power distribution branch, synchronously collecting voltage and current waveform data in real time, uploading the data to a central control system, generating a harmonic time domain database, and carrying out the real-time collection of the data; the method is used for reflecting power disturbance states. By constructing a distributed synchronous acquisition architecture and a harmonic time domain database, comprehensive perception and accurate identification of electric energy disturbance are realized, and a self-adaptive closed-loop control mechanism is established in combination with phase decoupling, reverse compensation and power evolution prediction, so that harmonic superposition and system resonance are effectively suppressed. According to the method, the electromagnetic compatibility and the system reliability of cooperative operation of the multiple charging robots are improved, and the equipment aging and operation and maintenance risks are reduced.

The invention is suitable for the technical field of hovercar control, and provides a thermal-vibration-weight collaborative optimization method of a high-power-density hovercar controller, and the method comprises the steps: constructing a three-dimensional housing structure based on fractal mechanics, achieving 35-45% of weight reduction through bionic design, and remarkably reducing the weight while guaranteeing the structural strength; thermal management, electromagnetic compatibility and vibration suppression collaborative optimization layout is established, a high-heating-power module is arranged near a heat dissipation air opening, and a sensitive control unit is arranged in a center damping area of a shell; a gradient material distribution scheme is adopted, a high-heat-conduction composite material is configured in a high-heat-flow area, and a high-damping material is adopted in a vibration sensitive area. Under the high-power working condition, the heat dissipation performance of the controller is improved, vibration transmission is reduced, the overall weight is reduced, and high-reliability control hardware support is provided for the hovercar.

The invention discloses an electromagnetic emission test method of an intelligent household electrical appliance, which simulates a dynamic interaction process by controlling multiple modules to run simultaneously according to a preset logic, and comprises the following steps: acquiring electromagnetic signals in real time and performing frequency domain conversion to obtain frequency spectrum distribution; identifying a target frequency band which generates energy convergence due to non-linear superposition and peak intensity of the target frequency band; obtaining a superposition waveform sequence and classifying a nonlinear superposition mode; identifying an abnormal interference mode by combining the peak intensity and a mode classification result; associating the abnormal frequency band with the module operation log, and analyzing an interaction time sequence and logic to determine a cause; a filtering or regulation strategy is applied based on the cause, whether the peak value is reduced is verified and a report is generated. According to the invention, through energy convergence frequency band identification, non-linear superposition mode classification, interference cause tracing, directional regulation and closed-loop verification, accurate diagnosis and root positioning of hidden transient interference are realized, so that the test depth is improved, the rectification efficiency is optimized, and the predictability of product electromagnetic compatibility design is enhanced.

The invention provides an electrocardiograph electromagnetic compatibility test data diagnosis method based on an intelligent sensor, and relates to the technical field of electrocardiograph electromagnetic compatibility test. The method includes generating structured test data. And calculating a theoretical interference reference threshold. And generating an initial interference judgment atlas arranged according to the interference time sequence. And constructing a dynamic compensation coefficient matrix, and injecting the dynamic compensation coefficient matrix into the initial interference determination map to obtain a dynamic interference determination map. And calculating the characteristic similarity between the real-time test data in each interference time sequence window and the dynamic interference judgment map, and diagnosing the electromagnetic compatibility state of the electrocardiograph. According to the invention, through multi-dimensional data acquisition and interference identification, through a dynamic reference threshold and a compensation mechanism, environment and equipment state changes are adapted, the diagnosis stability of a complex scene is improved, through real-time data comparison and traceability, the equipment state is rapidly judged, the interference source is positioned, the debugging time is shortened, and finally the measurement accuracy of the electrocardiograph is guaranteed.

The invention relates to the technical field of electromagnetic compatibility and signal processing, and discloses a multi-dimensional feature fusion-based electromagnetic leakage signal classification and identification method, which comprises the following steps of: preprocessing an original electromagnetic signal to obtain standardized data, extracting time domain, frequency domain and space domain features to construct a nine-dimensional feature vector, and extracting a three-dimensional feature vector; constructing an initial feature library and completing the initial feature library through a self-supervision verification mechanism, training the initial feature library through a CNN-LSTM fusion model with an attention mechanism to obtain a classification model, classifying signals to be identified, starting a self-supervision reinforcement learning mechanism optimization model according to an F1 score, and dynamically optimizing the feature library each month; the method solves the defects of the traditional technology, improves the recognition accuracy and the system adaptability, and can be used for cable information safety leakage protection.

The invention belongs to the field of flexible direct-current transmission power module tests, and discloses a multi-dimensional electromagnetic compatibility test system and method for a flexible direct-current transmission power module, and the method is characterized in that a dynamic power grid simulation unit simulates the electrical stress of the power module under a complex working condition by reproducing power grid limit faults such as direct-current short circuit and alternating-current harmonic waves; the broadband interference injection unit is used for superposing multi-band electromagnetic interference to simulate a composite interference scene according to the noise characteristics of the IGBT / IGCT switching process; the multi-physical field monitoring unit synchronously acquires key parameters such as electromagnetic field intensity, signal transmission, temperature rise and vibration, and analyzes module response under the action of multiple stress coupling in real time. According to the system, cooperative loading of power grid faults and noise is realized, limitation of a single interference source and a simple scene in a traditional test is broken through based on multi-physics field data fusion analysis, and the comprehensive evaluation precision of the anti-interference capability, the operation reliability and the safety of the power module in an extreme electromagnetic environment is improved.

The invention relates to the technical field of electromagnetic compatibility, in particular to a new energy automobile electronic part EMC (Electro Magnetic Compatibility) multi-dimensional simulation verification method, which comprises the following steps of: based on a geometric structure and material attributes of a new energy automobile electronic part, identifying an abnormal field intensity region, extracting a signal path and an electromagnetic wave incident direction, and analyzing an overlapping relationship between the signal path and the electromagnetic wave incident direction; according to the method, the electromagnetic field distribution and the interference source of the parts are accurately modeled and analyzed, the shielding and filtering design is optimized, the electromagnetic compatibility is improved, the interference coupling point is identified, the shielding effectiveness and the filtering effect are evaluated, the optimization policy is identified, the electromagnetic field distribution after optimization is analyzed, the fluctuation data of the external electromagnetic field is captured, and the influence evaluation list of the external electromagnetic field is generated. The reliability of the design under actual working conditions is ensured, electromagnetic interference is prevented, stable work of parts in a variable electromagnetic environment is ensured, the electromagnetic compatibility of the whole automobile is improved, the influence of electromagnetic interference on the functions of the new energy automobile is reduced, the design effect is optimized, and the performance and safety are improved.

The invention discloses a high-performance ship cable and a preparation process thereof, relates to the technical field of cables, and aims to solve the problem that an existing cable is insufficient in environmental adaptability, safety, electromagnetic compatibility and the like, the cable comprises a conductor, an insulating layer, a longitudinal waterproof structure, a shielding layer and a sheath layer from inside to outside, the conductor is of a multi-strand soft copper wire stranded structure, and the copper content of the multi-strand soft copper wire stranded structure is larger than or equal to 99.95%; the DC resistance at 20 DEG C is less than or equal to 0.01724 omega mm / m; the insulating layer is made of cross-linked polyethylene or polytetrafluoroethylene and can resist 1.5 times of rated voltage for 1 minute without breakdown; the longitudinal waterproof structure comprises a water-blocking tape and water-blocking paste; the shielding layer is of a double-layer structure, and the shielding effectiveness is larger than or equal to 60 dB The sheath layer is made of a low-smoke halogen-free flame-retardant material and contains an antioxidant and an ultraviolet light absorber, the preparation process comprises six steps of conductor preparation, insulating layer forming and the like, parameters are accurately controlled, the cable can work at the temperature of-40 DEG C to 85 DEG C, is salt-fog-resistant, waterproof and flame-retardant, is adaptive to the complex environment of ships and warships, and the operation reliability and safety are improved.

The invention relates to an alternating-current and direct-current integrated power supply system and a control method, a power conversion unit comprises a parallel high-frequency rectification module, an inversion module and a communication power supply module, and a direct-current side is connected in parallel to a common direct-current bus; the energy storage unit realizes energy interaction between a storage battery pack and a bus through a bidirectional DC / DC converter, and a matched health monitoring circuit acquires internal resistance, temperature and voltage data in real time; the dynamic voltage support unit is formed by connecting a filter network and a transient suppression device in series and is directly connected with a bus to suppress voltage fluctuation caused by load abrupt change; the electromagnetic protection unit integrates an input-stage surge protector, a cabinet body grounding copper bar and an anti-interference device, so that the electromagnetic compatibility of the system is guaranteed; the intelligent control unit is combined with the communication bus through the main controller, and the functions of multi-mode power supply switching, energy storage unit temperature compensation charging and cooperative fault protection are achieved. The system meets the AC / DC load hybrid power supply requirement through the modular design and the cooperative control strategy, and improves the reliability and adaptability of the power supply system.

The invention discloses a PCB wiring design method and system considering a pulse current fusing effect, and relates to the technical field of PCB design. The method comprises the following steps: based on a differential impedance design principle, including design rules of a differential microstrip line and a differential strip line, determining parameters such as the width, the thickness, the line spacing and the medium thickness of a wire so as to meet the impedance value requirement; based on the heat balance equation of the current-carrying conductor, a current conductor heating model and a current-carrying conductor heat dissipation model are established; on the basis of differential impedance design and in combination with the proposed binary particle swarm optimization algorithm, the electromagnetic compatibility factor can be comprehensively considered, the problems of low efficiency and electromagnetic compatibility existing in large-scale wiring design are effectively solved, rapid and accurate design of large-scale wiring can be achieved through an efficient calculation process, and the method is suitable for large-scale wiring design. The design efficiency and quality are remarkably improved, and the design requirement for the routing pulse fusing effect of a high-speed PCB signal is met.

The invention relates to the technical field of radio navigation and countering, and particularly discloses an unmanned aerial vehicle interference system and device based on phased array radar direction finding. The system comprises a phased array radar direction finding module, an environment electromagnetic propagation characteristic modeling module, an interference beam dynamic planning module and a digital beam forming interference module. Through constructing a three-dimensional electromagnetic propagation model and based on propagation loss and a multipath effect predicted by the model, a beamforming weight used for pre-compensating environmental influence is optimized and calculated, and finally an interference antenna array is driven to radiate an intelligent beam subjected to environmental pre-compensation, so that high-intensity interference is formed at an actual physical position of a target unmanned aerial vehicle, and the target unmanned aerial vehicle is subjected to environmental pre-compensation. Direction finding errors are overcome, and interference efficiency and electromagnetic compatibility are improved.

The invention discloses an electromagnetic compatibility fault prediction method for a pulse withstand voltage generator, and relates to the technical field of electromagnetic compatibility evaluation, and the method comprises the steps: collecting original signals of different circuit states of the pulse withstand voltage generator, extracting voltage ripple, current phase and magnetic field radiation frequency spectrum, and generating a time sequence monitoring data set; based on the time sequence monitoring data set, electromagnetic disturbance characteristics are extracted through deep analysis, a rule engine is built, and a fault probability and a fault type are output; triggering a plurality of suppression rules based on different fault types; after any suppression rule is executed, collecting the original signal again, and inputting the original signal into a pre-constructed risk assessment model to generate an interference suppression efficiency index; comparing the interference suppression efficiency index with a preset efficiency threshold value; if the interference suppression efficiency index is lower than the efficiency threshold value, generating a strategy compensation instruction and feeding the strategy compensation instruction back to the corresponding suppression step to iterate and adjust parameters; the electromagnetic interference suppression effect is improved.

The invention discloses a PFC (Power Factor Correction) circuit suitable for electrode high-voltage discharge. The PFC circuit comprises an EMI (Electro-Magnetic Interference) filtering module, a starting protection module, a PFC power conversion module and a PWM (Pulse-Width Modulation) switch type auxiliary power supply module which are connected in sequence. The EMI filtering module realizes bidirectional suppression of interference, and when the circuit is powered off, the bleeder resistor enables the common mode inductor and the differential mode capacitor to rapidly discharge, so that secondary interference is prevented; according to the PWM switch type auxiliary power supply module, a high-voltage area and a low-voltage area are isolated, and it is guaranteed that the power supply input pin of the control chip U2 / U3 can be within the normal working voltage; according to the invention, the control chip U2 limits the PWM duty ratio of the control chip U3 through the control logic, so that overcurrent protection is realized; when the MOS tube Q1 / Q2 is conducted, the resistor R22 consumes energy generated by discharging of the capacitor C21, meanwhile, resonance between the capacitor C21 and the energy storage inductor L2 is restrained, high-frequency electromagnetic interference is prevented, and electromagnetic compatibility of the whole system is achieved.

The invention relates to an electromagnetic compatibility and radio frequency coexistence framework, and belongs to the technical field of vehicle-mounted display and electromagnetic compatibility. The device comprises a display module and a control system which are arranged outside a vehicle body, the control system is provided with a cooperative control unit, an electromagnetic interference suppression module and a running state monitoring and adjusting module to form a closed-loop framework, and the closed-loop framework is used for dynamically managing display signals, power and a time sequence in the running process of the vehicle, suppressing conduction and radiation interference and controlling the running state of the vehicle. And the coexistence performance of the external display and the vehicle-mounted radio frequency system is ensured, and the electromagnetic compatibility regulations are met. Further, the system comprises an integrated topology unit, a coexistence monitoring unit and a strategy execution unit, driving time sequence shaping, backflow path constraint and power supply ripple shaping are achieved, and when interference exceeds a threshold value, the system is switched to a controlled display state. A shielding-grounding-filtering three-in-one layout and a driving time sequence shaping unit can be adopted. According to the invention, the safety and reliability of external display in the aspects of electromagnetic compatibility, radio frequency coexistence and service life management are ensured.

The invention discloses an intelligent switching control method and system for a double-voltage automobile generator, and relates to the technical field of automobile electrical control, and the method comprises the following steps: S001, constructing a frequency response baseline of an automobile power distribution network, and calibrating an inductance parameter of a wiring harness and a capacitance parameter of a filter based on frequency response measurement data; and generating an inherent frequency distribution diagram for reflecting the dynamic electrical characteristics. According to the method, the frequency response base line and the harmonic characteristic spectrum are constructed, so that accurate identification and dynamic prediction of the resonance risk are realized; avoiding the inherent frequency by adopting a multi-level control frequency planning strategy; virtual impedance and an active damping mechanism are introduced to improve the switching stability; and closed-loop optimization control is constructed in combination with residual signal feedback, and continuous convergence of the control performance is realized. According to the overall scheme, the stability, robustness and electromagnetic compatibility of the voltage switching process are improved, and safe operation of the double-voltage architecture under complex working conditions is guaranteed.

The invention provides a miniaturized broadband non-reflection filtering antenna and communication equipment, and relates to the field of communication antennas. The antenna comprises a hybrid coupling resonance system and a matched absorption network, wherein the hybrid coupling resonance system comprises a main radiation groove which is formed in a metal floor and is of a split ring structure, and two parasitic radiation grooves which are of a U-shaped structure and are located on the two sides of the main radiation groove respectively; the matching absorption network comprises an absorption resistor connected with the feed microstrip line in parallel and an absorption microstrip line connected with the absorption resistor in series. According to the embodiment of the invention, the absorption circuit is integrated on the structure, so that the antenna has the non-reflection characteristic in the range of 1.27-2.31 GHz far beyond the radiation bandwidth, the defect that the radio frequency front-end performance is deteriorated due to in-band reflection and out-of-band energy reflection back to a transmitting channel of a traditional antenna is effectively overcome, and the electromagnetic compatibility and the linear characteristic of the whole system are remarkably improved.

The utility model discloses an electromagnetic compatibility assessment device, and belongs to the technical field of wireless communication. The equipment comprises a data processing module, a signal generator module, a low-frequency / high-frequency amplifier, a combining unit, a shielding frame and a power supply module, and accurate evaluation of the electromagnetic compatibility of the weak current equipment is realized through modular design. The signal generator module adopts a multi-band vector signal generator to generate configurable interference signals; the low-frequency amplifier and the high-frequency amplifier respectively adopt independent high-precision amplification circuits; and the combining unit couples the two paths of signals into a composite interference signal and outputs the composite interference signal. The shielding frame is made of double-layer aluminum magnesium alloy and is combined with a metal machine frame to form a composite shielding system. And the data processing module regulates and controls parameters in real time through the touch screen, analyzes response data of the tested equipment based on an FFT algorithm, and generates a visual evaluation report.

The application relates to the technical field of high-voltage switch cabinets, in particular to a high-voltage switch cabinet convenient to maintain, which comprises a cabinet body and a cabinet door arranged on the cabinet body, a through hole extending along the arrangement direction of the cabinet door and the cabinet body is arranged on the cabinet door, an observation window, a shielding plate with mesh holes and a shielding net are arranged on the cabinet door, the mesh holes of the shielding plate and the shielding net are different in size, the observation window, the shielding net and the shielding plate are sequentially arranged along the arrangement direction of the cabinet door and the cabinet body, and the observation window, the shielding plate and the shielding net are all located on the surface of the cabinet door close to the cabinet body and cover the through hole. The shielding plate with mesh holes and the shielding net are arranged to form a multilayer electromagnetic shielding structure, the shielding plate and the shielding net can filter electromagnetic interference of different frequencies in a synergistic manner, and the electromagnetic compatibility is significantly improved.

The invention discloses an electromobile electromagnetic compatibility testing device, and relates to the technical field of electromagnetic compatibility testing, the electromobile electromagnetic compatibility testing device comprises a shielding box, the upper side of the shielding box is fixedly connected with a control box, and one side of the control box is provided with a manipulator used for clamping an electromobile motor to go in and out of the shielding box; one side of the manipulator is provided with an opening and closing mechanism used for opening and closing the entrance, the lower side of the control box is slidably connected with a load simulation circuit box used for regulating and controlling a power supply and emitting high-energy pulses through a circuit, and one side of the load simulation circuit box is fixedly connected with a second handle. One side of the second handle is provided with a wiring terminal, and the wiring terminal is fixedly connected with the load simulation circuit box. A dynamic test platform capable of highly simulating a real world complex scene is created, and the tested motor is driven to move along a U-shaped track in the shielding box through a precise mechanical structure; and working conditions such as straight running, steering and backing of the vehicle can be accurately reproduced.

A battery pack with electromagnetic compatibility (EMC) for an electric vehicle is presented that includes a battery pack housing, at least one battery module enclosed within the battery pack housing, and an electronics assembly enclosed within the battery pack housing, in which the electronics assembly comprises a DC-DC converter and an electronics assembly casing, wherein at least one of the electronics assembly and battery pack housing includes an electromagnetic interference (EMI) shield to enable EMC. The electronics assembly includes a battery management system (BMS) circuit board and a DC-DC converter control circuit board and a DC-DC converter power electronics board. The electronics assembly is of substantially a same dimension of a battery module, in which the EMI shield comprises at least one of a metallic screen, metallic wires, a metallic tape, a metallic sheet, a metallic coating, paramagnetic materials, carbon based materials and metallic and / or carbon particle-infused composites.

The invention relates to the technical field of electronic design automation, and provides an intelligent three-dimensional design optimization system for an ink-jet circuit board. The system comprises a field programmable gate array core control module, a microcontroller co-processing module, a multi-channel stepping motor driving module, a multi-mode communication interface module, a sensor feedback and state monitoring module and a three-dimensional layout optimization structure. High-precision real-time control and management are realized through heterogeneous cooperation of the programmable gate array core control module and the microcontroller cooperative processing module; in cooperation with multi-channel stepping motor driving, multi-mode communication and sensor feedback, a three-dimensional layout optimization structure is used for carrying out system space optimization on components, signals and a power supply, and heat dissipation, electromagnetic compatibility and signal integrity are remarkably improved. According to the system, the control precision and the real-time monitoring and remote management efficiency are effectively improved, the response speed, the operation stability and the maintainability of the system are enhanced, and high integration level and high reliability are achieved.

The invention provides an integrated antenna integrating Beidou, low-orbit and Tiantong satellite communication and high-precision navigation positioning. A low-orbit satellite microstrip antenna, a GNSS high-precision microstrip antenna, a Tiantong microstrip antenna and a Beidou short message microstrip antenna are sequentially stacked on the upper surface of a PCB in a conical mode. A shielding cover is arranged on the lower side of the PCB; antenna radiation patches of the low-orbit satellite microstrip antenna are arranged on the outer edges of the upper surface and the lower surface of the low-orbit satellite antenna substrate and are not covered by the GNSS high-precision microstrip antenna; circuits of the low-orbit satellite microstrip antenna and the sky-pass microstrip antenna are arranged on the upper surface of the PCB circuit substrate. And circuits of the GNSS high-precision microstrip antenna and the Beidou short message microstrip antenna are arranged on the lower surface of the PCB. According to the invention, the four-in-one combined design of the antenna, the low-orbit satellite antenna, the Beidou short message antenna and the high-precision navigation antenna is adopted, so that the problem of performance insufficiency when each antenna is used independently is solved, complementation among the antenna, the low-orbit satellite antenna, the Beidou short message antenna and the high-precision navigation antenna is realized, and the cost is reduced; the electromagnetic compatibility between the antennas is improved through frequency band and polarization isolation design, and the stability of a communication link is guaranteed through interference resistance of the peripheral low-orbit satellite antenna.

The invention discloses a circuit board testing and quality screening automation method and system, and aims to solve the problems of low efficiency, insufficient precision and imperfect quality control of traditional circuit board testing. Precise positioning of the circuit board is achieved through the high-precision X / Y / Z three-dimensional positioning mechanical arm, parallel testing is conducted in combination with equipment such as a multi-channel oscilloscope, a signal source and a spectrum analyzer, and the testing efficiency is improved. Temperature and humidity control testing is carried out through the environment simulation bin, the thermal imager scans temperature distribution of the circuit board, a high-precision instrument is used for detecting signal integrity and analyzing electromagnetic compatibility, and the performance of the high-speed circuit board is ensured. A machine learning algorithm predicts potential faults, a test process is optimized, an automatic sorting system is adopted to separate qualified and unqualified circuit boards, and high consistency and high reliability of product quality are ensured. Through the automatic and intelligent testing process, the production efficiency, the quality control capability and the testing precision are greatly improved, and the labor cost and the production risk are reduced.

The invention belongs to the technical field of electromagnetic compatibility design, and discloses a circuit topology and frequency-dependent inductance type selection design method considering frequency-dependent parameter influence and used for a wide-band multi-order EMI filter. According to the method, the problem of EMI filter high-frequency insertion loss deformation failure caused by the fact that actual source impedance, load impedance and filtering branch impedance change along with frequency is considered at the same time, and the method capable of rapidly and simply generating insertion loss of various EMI filtering topological structures is provided. Therefore, the target inductance value frequency spectrums on the standard exceeding frequency points under different filtering topologies can be accurately and quickly calculated; calculating a required maximum design coefficient according to the relative permeability spectrum of the frequency-dependent inductor with the high broadband attenuation rate, guiding the design of the spatial structure and the number of turns of the inductor of the filter, and evaluating the optimal filtering topology by comparing the maximum design coefficients under different topological structures with the same order; therefore, the accuracy of topology selection and inductance design of the EMI filter is improved, and the development cost of the EMI filter is finally reduced.

The invention discloses a flyback conversion circuit, which comprises N flyback conversion sub-circuits and an input power supply circuit, and is characterized in that the input end of each flyback conversion sub-circuit is connected with the output end of the input power supply circuit; the flyback conversion sub-circuit comprises an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit and M power conversion circuits; the first input end of the active absorption circuit is connected with the first end of the clamping capacitor, the second input end of the active absorption circuit is connected with the first end of the input filter capacitor or the second end of the input filter capacitor, and the first output end of the active absorption circuit is connected with the first input end of the output filter circuit. The second output end of the active absorption circuit is connected with the second input end of the output filter circuit. By adopting the design of multi-path staggered conduction control and unified energy absorption, the power conversion efficiency and power density of the circuit can be effectively improved, the voltage stress of the device is reduced, and the electromagnetic compatibility is improved.

The invention discloses a dual-drive electromagnetic interference suppression method and device based on random PWM and impedance matching, and relates to the technical field of power electronics and electromagnetic compatibility, and the method comprises the steps: constructing an instantaneous PWM frequency modulation model based on a random PWM mechanism; determining a frequency dynamic disturbance boundary constraint function; constructing a digital controller with a spectral domain feedback function; based on an instantaneous PWM frequency modulation model, a frequency dynamic disturbance boundary constraint function and a digital controller, double-drive electromagnetic interference suppression is carried out on the high-frequency and high-density power electronic system based on multi-harmonic observation and feed-forward compensation. By constructing a frequency spectrum decoupling-impedance reconstruction-collaborative suppression system, the technical bottlenecks of large size and narrow coverage range of single random PWM modulation of a traditional passive filter are broken through, and the filter has the advantages of wide frequency band coverage and high suppression precision.

The invention discloses an electromagnetic compatibility detection method and device of a rail transit signal system and electronic equipment, and relates to the technical field of electromagnetic safety. Determining an actual electromagnetic compatibility area corresponding to the equipment according to the actual distance between the actual installation positions of the multiple pieces of equipment of the rail transit signal system and a target reference line on a rail; and determining the electromagnetic interference risk condition between the relation pairs based on the electromagnetic interference information of the actual electromagnetic compatibility area corresponding to the equipment. According to the method, the electromagnetic interference scene of the actual rail transit signal system is analyzed to cover the random and coexisting electromagnetic interference combination of the field, so that the confidence coefficient of the risk assessment result in the complex electromagnetic environment of the field is improved, and the analysis is ensured to cover the random and composite scene which cannot be reproduced by the standard test; moreover, the electromagnetic interference risk condition between a relation pair formed by a plurality of devices in the rail transit signal system is determined, that is, systematic evaluation of complex electromagnetic interaction is realized through system-level analysis.

The invention relates to the technical field of interference suppression, in particular to an electromagnetic compatibility optimization method and system for a ship shaft frequency converter, and the method comprises the steps: carrying out the term-by-term judgment of sensitive interference energy, current errors and switching loss after the discretization and jump limitation based on a frequency sequence, and screening out a boundary-crossing sequence, the genetic algorithm executes cross combination and amplitude superposition in the residual sequence, a new frequency set is formed through transformation and rearrangement, frequency points are distributed in a plurality of intervals to be reorganized, the switch state is predicted and updated one by one through Kalman filtering, observation residual errors are corrected in real time, and the frequency points are reorganized. The harmonic distortion rate, the radiation intensity and the instruction change amplitude are synchronously output by taking the time index as a sequence, the deviation is compensated at the amplitude and phase level, the harmonic index and the radiation index are controlled in an agreed range, the switching loss and the instruction change are within threshold values, and a complete closed loop covering frequency generation, harmonic correction and sequence updating is formed.