Interharmonics Power Losses Estimation in Power Transformer fed High Power Cycloconverter Drive

High power cycloconverter (CCV) fed drives are widely used in mining plants for ore processing. Actually, transformers for CCV are manufactured under IEEE Standards for rectifier power transformers, considering harmonics losses only. However, when the drive operates at full power and variable speed, interharmonics currents can cause additional losses and overheating. In this work, the analysis of an actual CCV-drive with experimental measurements is presented, including a model for estimation of the interharmonic losses, considering the most relevant spectral components around the fundamental component. These losses are relevant and new considerations for transformer design are proposed.