Choosing variable-frequency drive systems for the mining process units Natalia Kugusheva, Alexander Semenov, Ilya Yakushev, Svetlana Pavlova, Ayaal Egorov and Oleg Fedorov E3S Web Conf., 244 (2021) 09011 Published online: 19 March 2021 DOI: 10.1051/e3sconf/202124409011