Solar Simulator on the Basis of Powerful Light-Emitting Diodes Oxana Aldoshina, Vyacheslav Yugay, Nurbol Kaliaskarov, Ulan Esenjolov and Saltanat Nesipova MATEC Web Conf., 155 (2018) 01035 Published online: 28 February 2018 DOI: 10.1051/matecconf/201815501035