Static frequency changers

Static magnetic frequency changers gained wide industrial application during the last 15 years. The rating of individual units increased from 50-kW active power output to 3000 kW, and larger units are contemplated. This paper deals with problems that are of primary importance for larger units only. The design procedures improved during the last years due to increased knowledge of the aftersaturation reactance of core-coil assemblies and due to new information available for core losses at high and distorted flux densities. The stability limits of filtered frequency changers are discussed and some new applications are mentioned.