Hyun-Woo Kim, Yu-Ran Go, Myung-Hwan Min, Tae-Pung An, Tae-Hoon Lee, 2019, Study on
                           the Parallel Operation of Active Balancer for Unbalanced Load in AC Electric Railway
                           System, The transactions of The Korean Institute of Electrical Engineers, Vol. 68,
                           No. 11, pp. 1489-1496
