Beschreibung
High power density converters are enabled by WBG semiconductors, taking advantage of higher switching frequencies. It however yields increased levels of noise in ranges covered by EMI standards, leading to difficulties on filtering both differential (DM) and common mode (CM) noises. In this work, various aspects of the noise source are analysed: coupling, emissions, converters, and switching events. Noise sources of the most relevant converters and inverters for photovoltaic application are investigated. As semiconductors switching waveforms also influence the frequency spectrum, the most relevant non-ideal effects are investigated: rise and fall times, overvoltage, oscillations and soft-switching. Requirements and properties of filter inductors and capacitors are presented, including magnetic core materials and windings, besides capacitors types and materials. A comprehensive investigation about EMI filter design, focusing on a one-phase gridconnected 2.3 kW full-bridge PV inverter is presented. Simulation and experimental assessments indicate a strong influence of the components self-resonance and coupling effects on the filter response, which worsen at higher frequencies.
