Investigation on Conducted Commn Mode Electromagnetic Disturbance for Photovoltaic Current Source Inverter

Common mode (CM) voltage and its resulting conducted CM electromagnetic disturbance emissions are strictly limited by regulations in photovoltaic (PV) current source inverters (CSIs). In order to study the CM conducted disturbance emission level of CSI, it is often necessary to establish a full circuit simulation model to predict the electromagnetic interference (EMI) spectrum of the power port, which consumes a lot of computing resources. As an alternative, analyzing and extracting the CM noise propagation path of the CSI and building the CM equivalent circuit model can save simulation time. In this paper, a CM equivalent circuit is established to predict the CM conducted EMI of CSI, and the influence of circuit parasitics is considered. In addition, the parasitic parameters of the inductors are extracted by the fitting method, and the equivalent circuit model is appropriately simplified to improve the efficiency of the simulation.