Observer based online current offset compensation method for single-phase photovoltaic inverter applications

An online current offset compensation method is proposed for photovoltaic (PV) inverter applications. In order to detect a current offset in the system, a simple full order observer is designed. By assuming the current offset to be a DC component in steady state, the observer gain selection becomes extremely easy. After that, a simple feed-forward compensation method is applied to eliminate the current offset. The proposed method is experimentally verified by using a PV inverter prototype.