ELGi Equipment, Coimbatore, celebrated the second edition of the “State of the Future Art” themed ‘Technology Day’ at the Le Meridien, Coimbatore, on December 15, 2019. The event saw participation from 200+ employees, academia, and students from over 20 engineering colleges across India and industry thought leaders. Students were invited to author papers on “Energy Efficiency and Creating a Greener Environment”. This contest received more than 50 papers from engineering colleges which were evaluated and filtered at three levels through a presentation followed by a question and answer session. The three papers were selected as best paper for presentation for the Technology Day included “VFD Reliability Improvement – Grid Related Issue Causing Drive Failure?”, a paper from Amrita School of Engineering, Coimbatore. Ms. Janani Sunil, Mr. Sivakumar S. and Mr. Sidharth Easwar of first-year M. Tech. Power Electronics presented this paper based on their study under the guidance of Dr. A. Vijayakumari (Associate Professor, Department of Electrical & Electronics Engineering, School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore).

The gist of the awarded paper:

Very recent failure statistics of power electronic systems ascertained that failure of the diode/SCR (Thyristor) in the front-end rectifier has been registered as the major contributor in Variable Frequency Drive (VFD) faults. A proactive investigation on the VFD failure unfolding the most probable reasons has therefore been felt as the need of the hour.

Taking the cue from these statistics, the Amrita Vishwa Vidyapeetham, team directed their investigation on the question of whether the failure is triggered by the weak Indian grid or the customer site conditions. Through an intensive analysis and field measurements on industry installations of VFD, the team established that the SCR failure is due to harmonic resonance induced by volatile combinations of automatic PF correction capacitors at the customer sites and the uncertainty in the grid impedance. The team presented a few convincing case studies to corroborate their finding. They further suggested a signal decomposition-based solution for the protection of future VFD based air compressors.