Dry type transformers for power converters

Abstract

Dry type transformers differ from oil immersed transformers mainly in cooling conditions. Converter transformers generally involve more coils, distorted waveforms and high currents. This paper discusses the special cooling conditions needed for dry type transformers, focusing on novel calculation techniques and an easy approach to the design of coils. The paper further discusses the most important converter connections and winding layouts for converter transformers and reactance and eddy current calculations.