2004 zyxwvutsrqp 35fh Annual IEEE Power Elecrronics Specinlists Conference Anchen, Germany, zyx 2w4 The Influence of Passive EM1 Filters on Various Aspects of Electromagnetic CompatibiIity of ASD’s zyxwv A. Kempski R. Smolenski R. Strzelecki University of Zielona Cora University of Zielona Cora Gdynia Maritime University Zielona Cora, Poland Zielona Cora, Poland Gdynia, Poland zyx A.Kempski@iee.uz.zgora.pl R.Smolenski@iee.uz.zgora.pl rstrzele@am.gdynia.pI Email: Email: Email: Abstract- With the recent progress in power electronic devices employed in power converters an assurance zyxwvut of EMC performance of Adjustable Speed Drives (ASD) systems becomes a significant problem. This paper presents a comparative analysis of an influence of commonly used passive EM1 filters (line reactors, CM choke, CM transformer and sinusoidal filter) on various aspects of electromagnetic compatibility of ASD’s. 1. INTRODUCTION The many advantages of Adjustable Speed Drives such as high performances in dynamic response, efficiency, acoustic noise, size and weight require an application of fast switching transistors (usually IGBT zyxwvutsr - insulated gate bipolar transistor) and high switching frequencies of voltage source PWM inverters. However, fast switching inverters generate high slew rate (dvidt) of inverter output voltages and high common mode voltage at motor terminals. These counterbalance advantages of ASD’s by certain undesirable side effects, which can influence both external and internal electromagnetic Compatibility. A high level of electromagnetic emissions deteriorates electromagnetic environment and affects power supply quality. On the other hand, fast lGBT devices introduce new kinds of problems on the motor side of the converter such as premature winding failures, ground leakage currents, shaft voltages and bearing currents I1-51. The main source of EMC related problems in modem AC drives is the CM voltage, which results chiefly from unbalanced switchings of most popular two level three legs inverters. This instantaneous electrical asymmetry causes CM voltage, which appears in neutral point of the system. Steep slopes of CM voltage steps excite parasitic capacitive couplings inside of the motor and cables. Every step forces CM current to flow and can charge a motor shaA [4-51. If a shaft voltage exceeds a critical threshold value of baring oil film a shaft is unloaded in a form of a destructive bearing current (EDM Electric Discharge Machining). This paper addresses the problem of CM noise reduction in three phase PWM inverters by means of commonly used passive methods (line reactors, CM choke, CM transformer, sinusoidal filter). Based on measurements, both in the time and frequency domains, the comparative analysis of influence of passive EM1 filters on various aspects of internal and external electromagnetic compatibility has been presented. 11. EXPERIMENTAL RESULTS For the comparative analysis between drives with various passive filters the measurements in a drive comprised of two-quadrant 7SkW frequency converter and 1.5kW induction motor have been chosen as the case study. A. Drive withoutjiliei-s Main part of conducted electromagnetic emissions of ASD’s is formed in resonant circuits on the motor side of a converter as a corlsequence of switching of IGBT’s. However, the results presented in our earlier works show that the only small part of the CM current created on the motor side flows h o u g h the supply arrangement (LISN) because of an existence of an alternative path contains heatsink-to-DC link capacitance [6]. Fig.2, shows the waveforms of CM currents on the motor and the line side of the inverter. Fig.2. CM (:urnem on the line and mom sidc 0-7803-8399-0/04/$20.M) 02004 IEEE. zyxwvuts 970