Strong Electromagnetic Interference Environment Research Articles

Research on the rapid assembly algorithm of the wireless ultraviolet cooperative UAV formation.

Aiming at the problem that the strong electromagnetic interference environment restricts the communication of the Unmanned Aerial Vehicle(UAV) formation, which affects the rapid assembly of the UAV formation, a wireless ultraviolet cooperative UAV formation rapid assembly algorithm is proposed to realize the fixed-point assembly of the UAV formation in the airspace. First, the Ultraviolet(UV) light beacon model is used to realize the information interaction of the UAV formation. secondly, the UV four-node positioning algorithm is used to realize the three-dimensional positioning of the UAV formation. Combined with the method, the UAV formation can reach a consensus speed when assembling. The simulation results show that when there are more than 6 reference nodes, the three-dimensional space positioning accuracy can reach 96%. The assembly algorithm can realize the fixed-point assembly of the UAV formation, and can maintain the circular motion trajectory after the assembly is completed.

Design and research of image transmission systems with fiber bundles in environment of strong electromagnetic interference

In order to solve the problem of image stable transmission in electromagnetic interference environment, an fiber bundles image transmission system with the ability of anti strong electromagnetic interference was designed and developed. By using ZEMAX, the front objective lens and the rear eyepiece lens in the image transmission system was designed, respectively. And according to the initial aberration distribution of the objective lens and eyepiece lens, the system aberration was further optimized by using the optimized function and various operation numbers. The optimized results show that, the MTF value of each field of view of the objective lens is greater than 0.85 at the spatial frequency of 38 lp/mm, and that of each field of view of the eyepiece lens is greater than 0.3 at the spatial frequency of 120 lp/mm, which has high imaging quality. According to the structural characteristics of the selected objective lens, eyepiece lens, fiber bundles and CCD, the coupling device of system connection is designed and manufactured, and the image transmission system is built for the image transmission experiment. By analyzing the imaging quality and influencing factors of the system, the image brightness is improved by using the Gamma algorithm, and the high-quality transmission image is obtained.

Design of a Matching Network for a High-Sensitivity Broadband Magnetic Resonance Sounding Coil Sensor.

The magnetic resonance sounding (MRS) technique is a non-invasive geophysical method that can provide unique insights into the hydrological properties of groundwater. The Cu coil sensor is the preferred choice for detecting the weak MRS signal because of its high sensitivity, low fabrication complexity and low cost. The tuned configuration was traditionally used for the MRS coil sensor design because of its high sensitivity and narrowband filtering. However, its narrow bandwidth may distort the MRS signals. To address this issue, a non-tuned design exhibiting a broad bandwidth has emerged recently, however, the sensitivity decreases as the bandwidth increases. Moreover, the effect of the MRS applications is often seriously influenced by power harmonic noises in the developed areas, especially low-frequency harmonics, resulting in saturation of the coil sensor, regardless of the tuned or non-tuned configuration. To solve the two aforementioned problems, we propose a matching network consisting of an LC broadband filter in parallel with a matching capacitor and provide a design for a coil sensor with a matching network (CSMN). The theoretical parameter calculations and the equivalent schematic of the CSMN with noise sources are investigated, and the sensitivity of the CSMN is evaluated by the Allan variance and the signal-to-noise ratio (SNR). Correspondingly, we constructed the CSMN with a 3 dB bandwidth, passband gain, normalized equivalent input noise and sensitivity (detection limit) of 1030 Hz, 4.6 dB, 1.78 nV/(Hz)1/2 @ 2 kHz and 3 nV, respectively. Experimental tests in the laboratory show that the CSMN can not only improve the sensitivity, but also inhibit the signal distortion by suppressing power harmonic noises in the strong electromagnetic interference environment. Finally, a field experiment is performed with the CSMN to show a valid measurement of the signals of an MRS instrument system.

Online nondestructive testing for fine steel wire rope in electromagnetic interference environment

The diameter of fine steel wire rope (FSWR) is generally a few millimeters. Its magnetic flux leakage (MFL) signal is weak, and the number of magnetic sensors installed for defect detection is limited because of the small diameter. In FSWR production workshops, different kinds of machinery work together, deteriorating the power quality and making the spatial electromagnetic environment complex; the weak MFL is thus interfered with further. It is difficult to carry out online nondestructive testing (NDT) of FSWR in the process of manufacturing. In this paper we present a novel MFL method for FSWR NDT in a strong electromagnetic interference environment. We use a three-dimensional finite element method (FEM) to analyze the MFL signals. A simplified magnetic circuit is presented to excite the FSWR; the circuit comprises two half-sized radial magnetizing ring NdFeB magnets, and because there is no need for a magnetic yoke, the device is simple and light. A single Hall sensor is used to measure the flux leakage field. A stable performance power system is designed for the NDT power supply, which is not only resistant to voltage sags, but also has very low output noise. To enhance the signal-to-noise ratio (SNR) of the MFL defects signal, a signal conditioning and processing circuit are designed to enhance the detectability of signals in MFL data. The novel and small FSWR NDT system realizes on-line testing in an environment of strong electromagnetic interference, and for the experiment with a 1.5-mm-diameter wire rope twisted by 19 wires, the minimum damage of a pit on half of a wire can be identified.

Anti-Interference Measurement Methods of the Coupled Transmission-Line Capacitance Parameters Based on the Harmonic Components

The traditional measurement methods of capacitance parameters of coupled transmission lines bring large measurement errors under a strong electromagnetic-interference environment. To solve this problem, new anti-interference measurement methods based on harmonic components are proposed. First, the voltages and currents at the head end and the tail end of the transmission line are sampled synchronously based on global positioning system (GPS) technology, then they acquire the third harmonic components from the measured data with an interpolation fast Fourier transform algorithm, and substitute them to the calculation formulae, so that the power frequency interference signals are filtered as noise and the capacitance parameters can be accurately measured. The wiring diagram of line parameter measurement and the hardware structure of the measuring system based on GPS are given. The simulation results with PSCAD and an example of measuring two 200-kV coupled transmission lines are given. The comparison of measurement results between the proposed methods and the traditional methods is also shown.

The Simulation of Strong Electromagnetic Field Experimental Environment around On-Line Monitoring System for UHV Transmission Tower

Real-time on-line monitoring system for UHV transmission tower is located in strong electromagnetic interference environment, especially when the transmission tower encounters thunderstorm weather, lightning current can produce the stronger electromagnetic field near the power transmission tower, so the bad environment generated by strong electromagnetic interference determines the difficulty of analysis of strong electromagnetic field distribution, therefore, this design chooses to simulate strong electromagnetic field environment around the online monitoring system of UHV transmission tower in the laboratory, carries on the analysis, then summarizes its impact on the monitoring system of the wireless channel and puts forward protective measures.

The Design of Trigger Circuit for Power Thyristor

In this paper, for the strong electromagnetic interference environment, a kind of 6500V/1000A thyristor controller is designed. The controller includes a main trigger state detection module, an optical fiber communication module, a temperature detection module, a main controller module, and a trigger module. It highlights the thyristor trigger circuit and its corresponding detection circuit, this trigger circuit can provide a strong trigger pulse to ensure a reliable triggering of thyristors at any moment, the detection circuit can improve the reliability of the system.

The Research of The Pulse Power Source Sequential Control System

The pulse power source; Control system; Sequential control; Trigger control Abstract. In this essay, the working process of Capacitor-Based Pulsed-Power System and the requirement of the sequential control component applied in such system has been discussed. Based on that, further description of the composition and working principle of the sequential control system has been made .The diagram of each block of the sequential control system are displayed to illustrate the working process in engineering application and problems would confront in engineering designing process. Finally, the charging and discharging test and electromagnetic emission experiments have been conducted and prove that such sequential control system can function stably and reliably in strong electromagnetic interference environment and it also has good expansibility.

Key technology on all-plastic optical life detection instrument

Plastic fiber image bundle with 250 single fiber diameter, 4096 pixels, 15 m length is fabricated. The result indicates that 25% of the input image remains after it has translated though the 15m fiber bundle, which can meet the need of eye observation or CCD image capture. Based on the key component of image bundle, the eye observation life detection instrument prototype and intelligent life detection instrument prototype connected with CCD, image capture card and portable computer are designed and produced. The effectiveness of researching and rescuing the person from danger is demonstrated. The system can be used not only for researching and rescuing the buried person, but also for video monitoring some special occasions, such as strong electromagnetic interference environment, security department and explosive places.

Technology of CAN Bus Used in the Pulse Power Source Control System

he Pulse power source (PPS) control system works in the environment of strong electromagnetic interference, to ensure the system's stability and reliability in the conditions of the multiple PPS modules' working synchronously in timing sequence the CAN bus driver design and optical communication interface design are adopted. The overall design of the PPS control system is proposed after analyzing the principle of PPS. The circuit of data collection of high voltage and high current is designed. The actual experiment proved that this system has high resistance to strong electromagnetic interference and it can work stably and reliably.

An Improved Synchronization Mechanism of SERCOS III in Strong EMI Environment

Strong EMI (Electro-Magnetic Interference) brings the problem of packet error and following retransmission. Especially in motion control area, the widely used Real-Time Ethernet SERCOS III will be seriously affected by EMI from the motor and other power electronic devices. This paper focus on the behaviors of synchronization mechanism of SERCOS III in a strong EMI environment. Strong EMI affect the precondition of SERCOS III’s synchronization mechanism, and the precision of synchronization is highly affected. A Timed Petri Net model of the former mechanism in packet error environment is created and simulated in the Timed Petri Net simulation software CPN TOOLS. The simulation results indicate that the synchronization error is up to about 0.5 to 45 times of retransmission cycle time. This error is unacceptable in motion control area. Then, the paper provides an improved synchronization mechanism, and similar simulation is run. Simulation results indicate that synchronization error is eliminated by the improved mechanism.

Two dimensional fiber-optical accelerometer

A new type of simple and reliable two-dimensional fiber-optical accelerometer is developed to measure constant (dc) and variable (ac) accelerations simultaneously in two perpendicular directions (vector acceleration) with a linearity error of less than 0.1%. The sensor is based on a deflection of a uniform round elastic cantilever beam sensed by an optical lever and a continuous position optical sensor. The accelerometer has a resolution of 0.3 m s−2, dynamic range of 62 dB, −48 dB crosstalk and a natural frequency ω=1970 rad s−2 , when accelerations of up to 400 m s−2 are measured. The compact shielded construction, high responsivity photosensor and high power photodiode make the proposed sensor stable in the environment of strong electromagnetic interference. Varying the sensor’s parameters, the proposed sensor can be designed to have almost any desired response and sensitivity, and natural frequency.