A single-phase two-wire grid-connection PV inverter with active power filtering and nonlinear inductance consideration

This paper proposes a single-phase two-wire (1φ2W) PV inverter system with power quality control and nonlinear inductance consideration. The proposed system can fully or partially perform active power filtering, process PV power, eliminate harmonic currents, improve power factor, and take into account nonlinear effect of its output filter. In the system, only is source current sensed to achieve power-quality control and maximum-power-point-tracking feature, reducing cost significantly. To prevent output current from exceeding switch ratings, inverter current is properly controlled through a current estimator and a defined limit circle. A self-learning algorithm is also proposed to determine nonlinear inductance, which can increase accuracy of the estimated current. Simulations and experimental results have verified the feasibility of the proposed PV inverter system and the algorithm.