Methods and Equipment to Provide Electromagnetic Compatibility in Marine Power-Supply Systems

Abstract

The problem of electromagnetic compatibility during operation of electronic ship systems is quite urgent thanks to the presence of a large number of powerful semiconductor converters and electric equipment that produce a high level of noise. On the other hand, communication, navigation, and automation facilities use low levels of useful signals. Semiconductor converters generate pulse voltages to electric mains because of the switching process. The spectrum of the pulse interference ranges up to radio frequencies. The possible conductive and radiated noises are limited by the requirements of electromagnetic compatibility. To meet these requirements, designers should introduce new solutions for noise suppression. In this work, a method for noise suppression by means of shifting the switching frequency of a converter has been suggested. A change in the converter frequency by 30% can result in a decrease in the noise by more than 20 dB. The experiments have shown that a level of noise decreases by 10 dB for 20% of frequency shifts.