DC-link input EMI filter design in a centralized architecture PV inverter: Impedance approach

This paper focuses on the conducted electromagnetic interference emissions generated in a grid connected PV system. It addresses the issue of the source impedance pertaining to the placement of the EMI filter. It evaluates the DC-side impedance of the inverter to optimize the attenuation performance of the EMI filter. Proposed design analyses and procedures for the DC side intermediate EMI filter are presented. The impedance interaction approach is employed at both, the PV side and the DC/DC converter interface, to ensure the converter stability at Maximum Power Point Tracking (MPPT) and to comply with the applicable EMC standards. It proposes a plug-n-play EMI solution for large centralized PV systems. Experimental results show that the implementation of the EMI filter at the DC feed has effectively attenuated the EMI noise to an acceptable level using the DC-side impedance approach.