Ultracapacitor-based plug & play energy-recovery system for elevator retrofit In English E. Oyarbide, I. Elizondo, A. Martínez-Iturbe, C. Bernal and J. Irisarri, “Ultracapacitor-based plug & play energy-recovery system for elevator retrofit,” 2011 IEEE International Symposium on Industrial Electronics, Gdansk, Poland, 2011, pp. 462-467, doi: 10.1109/ISIE.2011.5984069. You can access this paper through IEEEXplore database Ultracapacitor-based plug & play energy-recovery system for elevator retrofit | IEEE Conference Publication | IEEE Xplore or under request