Low Frequency Conducted Emissions of Grid Connected Static Converters

Abstract

Pulse-width modulated rectifiers are nowadays commonly used for AC to DC power conversion. PWM rectification technology is very effective and allows for bidirectional power flow with the possibility of power factor improvement and low-order harmonic emission limitation. Unfortunately, employed PWM boost topology results with generation of input current harmonic distortions in a frequency range tightly correlated to modulation frequency. PWM carrier frequency and its harmonic components in typical applicatechnology, uninterruptible power supply systems, reactive power static compensator, harmonic active filters [1-61.This technological trend significantly increases harmonic emission spectrum within higher frequency ranges correlated with modula tion carrier frequency. Therefore, typically used harmonic limitation up to 40th order in many contemporary applications needs to be extended up to 9 kHz, which is the lower limit frequency of typical conducted electromagnetic interference (EMI) analysis interest.tions are usually located in frequency range from single kHz up toIn recent years, significant increase of harmonic emission into the hundreds of kHz. Increase of harmonic emission in this particular power grid is observed, which results with the increase of incomfrequency range can be disturbing for other sensitive systems, patibility risk in frequency range from above 40th order harmonic therefore can cause lack of electromagnetic compatibility. Interup to 9 kHz and within CISPR A band (9-150 kHz). In this frequency ferences in low frequency range are increasingly frequent EMC range also a number of power line communication systems are issue because of extensive use of low power PWM rectifiers and used, therefore their immunity levels have to be coordinated with significant increase of rated power of individual converters, which the expected conducted EMllevels originating from grid connectalready reach several MW. Presented comparison of current hared PWM converters [7-131.monic emission spectra of PWM rectifiers with relation to classic diode rectifiers is focused on frequency range of 2 to 9 kHz, for which emission limitation rules are currently under development.New class of EMC problems arising in low frequency range in power system are underlined as a result of increased harmonic emission in frequency range of 2 to 9 kHz.

Ultrawideband combined vibrator-slot Clavin type radiator

“…ВСТУП Перехідні процеси в природі та техніці відіграють важливу роль як ключові особливості процесу передачі інформації. Поширення потужних перетворювачів на основі ширинно-імпульсної модуляції та випрямлячів на сонячних електростанціях та сучасних електромобілях вимагає вивчення його завад, що діють на інші пристрої [1]. Перехідні процеси можуть спричиняти помилки в лініях передачі цифрових сигналів та переривати роботу пристроїв радіочастотної ідентифікації (RFID) через їх надширокосмуговий характер [2].…”