Active output filter under nonlinear load condition for solar powered unmanned aircraft system

In this paper a new electric power structure for solar powered unmanned aircraft system is proposed. The presented topology is a prospective improvement to both Solong and Zyphyr models. The proposed UAS model utilized Zyphry UAS by using ac bus-line instead of dc bus-line to supply the propellers. The system involves PV array, lithium sulfur based energy management system, dc bus-line, inverter, active output filter (AOF) and ac bus-line. AOF topology is utilized to reduce the power conversion system size. The system is investigated under nonlinear load condition with closed-loop control strategy. Active compensation resistance technique control is deployed to ensure high quality sinusoidal line voltages. It introduces an emulated resistance in series with H-bridges stage, this active resistance will create an injected voltage across it to damp unwanted harmonics created from the nonlinear load. The obtained simulation results of voltage and current waveforms prove the feasibility and the accuracy of the proposed system.