Performance evaluation of single-stage photovoltaic inverters under soiling conditions

Abstract

Fly ash soiling effects are an air pollution consequence, especially during the heating season, and have considerable influence on the ability of urban photovoltaic (PV) systems to operate as an electricity supply grid. In this paper, an experimental study of soiling influence on PV systems with single-stage inverters was conducted on the hybrid micro-grid example. PV panel field measurements showed that soiling induces not only well-known maximum power point (MPP) tracking problem, but also reduces available power up to 30 %. Laboratory comprehensive tests with PV panels measured and emulated characteristics showed that, due to soiling, grid forming single-stage inverters operate with stability operation problems that can lead to energy production cessation. A reliable MPP estimation providing PV system with sufficient power reserve is necessary for hybrid micro-grid uninterrupted operation. In case of MPP tracking, it is necessary to establish additional limitations for the DC voltage to keep grid inverter functionality.