Study On The Key Technology Of EMC And Security Of Mine Motor Drive Inverter

With the number of the sensitive electronic equipment and electrical equipmentin coal mine increasing, the research of the conducted harmonic interference andradiated interference of the underground electrical equipment is becoming more andmore important, but the related research is still not deep, especially for the mainelectromagnetic interference source, mine inverter, is still inadequate, can not form arelatively complete standards and norms, which seriously restricts the upgrading stepsof the coal mine electrical equipment technology.This paper focuses on the EMC problem bringed by mine inverter in the use ofthe present results, reviewes the industry standards and the previous research resultsabout mine inverter at home and abroad, makes the further study on the main circuitharmonic of mine inverter based on the theory and experimental achievements, andmakes design and discussion about some commonly used filtering measures. In theharmonic study, the paper mainly makes research on the harmonic spectrum analysisof the output differential mode voltage about the commonly used SPWM andSVPWM mine inverter through the method of double fourier analysis, which revealsthe distribution of output harmonic in the carrier band and the fundamental band. Tomake analysis of the effect by harmonic interference on the safe operation of themotor, and study the influence on the torque of the asynchronous motor by converteroutput voltage harmonics, the equivalent circuit model is built for asynchronousmotor, on the basis of which the parameters of the output side filter LC is designedand optimizated. Through comparing different characteristics of the line side voltageharmonics of the thyristor tube, diode and PWM rectifier structure commonly used inmine inverter, analyse the four quadrant transformation of the mining inverter rectifieris necessary to improve the performance of it’s EMC, and study the line sideharmonic of the PWM four quadrant rectifier on the basis of theoretical analysis,Combined with spectrum analysis of the line side harmonic of the dual PWM inverter,the inductor’s parameters is designed and simulated. Given the harmoniccharacteristics of PWM rectifier is not ideal, in order to reduce the interference on thepower system in coal mine, put forward the advice that of isolation transformer shouldbe installated in the line side, and study the principle and selection of the isolationtransformer.In order to improve the anti-interference performance of mine used inverter,reduce unsafe factors to the staff by the leakage, the control system, the main circuit and the shell are generally required to take appropriate measures for grounding,Aiming at two aspects of the transmission line and the grounding shell safety andEMC grounding, the mining inverter grounding requirements were researched andanalysed, can well reduce the maintenance cost of inverter in EMC, to improve itssafety and reliability in runtime. As a kind of electrical equipment used in explosiveenvironment, the inverter is generally equipped with explosion-proof enclosure, in thedesign of flameproof enclosure, The manufacturers generally only consider itsperformance in terms of compression and explosion, etc. but consider less influenceof the electromagnetic radiation shielding of the flameproof enclosure, and theflameproof enclosure generally exist apertures, which brings a way to leakelectromagnetic radiation. By establishing a theoretical and simulation model, thepaper studied the shielding effect of the high frequency electromagnetic radiation ofthe Shield, put forward some suggestions on the flameproof shell hole sealingmeasures, to provide guidance on the design of flameproof enclosure in the future.