Integrated LCL filters used in grid-tied photovoltaic power systems for conducted EMI reduction

Abstract

In this paper, the integration technique of magnetic components of a LCL filter used in grid-tied photovoltaic (PV) power systems for conducted electromagnetic interference (EMI) reduction, especially common-mode (CM) emission, is proposed. Two CM chokes of a LCL filter are integrated into single unit by using an UIU magnetic core. The winding configuration and approximation of differential-mode (DM) and CM inductances of proposed technique are also presented. The DM and CM EMI reduction performances of grid-tied PV power systems without any filter inserted, with conventional separated CM chokes, and with proposed integrated CM choke are evaluated and compared. From the experimental results, it can be concluded that the proposed integrated LCL filter is not only having high EMI attenuation rate comparing to a conventional LCL filter, but also can reduce total physical size, weight, and production cost of grid-tied PV systems.