Power Converters Electromagnetic Emissions with Methods to Measure, Compare and Reduce Noise Fields

Abstract

Power electronic converters find widespread applications in the present times. However, they have been known to be rich sources of electromagnetic emissions. The converters are required to operate in compliance with their electromagnetic environment, for which they must adhere to emission limits imposed by the standards. The power converters are duly tested, and their emission levels are measured and checked for compliance. Therefore, understanding the emission mechanism is necessary to design a power converter that will satisfy the EMC requirements. In addition to the switches, parasitic elements, which are invariably present in every circuit, play a crucial role, especially in the higher frequency range, in degrading the EMC performance of converters. The present chapter takes up these aspects and discusses the reasons behind emissions and the roles played by switch characteristics and parasitic elements. Demonstrations through simulations and computations are presented all along with the discussions, and inferences are accordingly drawn. Finally, the standard specifications for emission measurements and analysis through measuring EMI receiver are briefly introduced. A few popular methods to reduce emissions are demonstrated. The final improvement in the EMI performance is shown with the help of EMI receiver output, in accordance with the CISPR standards.