Nanocrystalline Cores for Common Mode Current Suppression in Electrical Ship Propulsion Systems - a Case Study

Electric ship propulsion system is a strong trend to increase efficiency under all operation conditions. In our special case, however, the system of electric power generation, distribution and propulsion appeared to be non-conformal with all EMC requirements for ships - leakage currents (inclusive capacitive effect) exceeded limits defined by Lloyd's rules - despite single components fulfilling specifications. After analysis of electrical, mechanical and given dimensional requirements and conditions, we developed oval shaped nanocrystalline cores for common mode suppression, being consistent with mechanical and thermal requirements in this certain environment. This article presents the requirements, the design of cores, and the results in terms of common mode currents.