Investigations into the minimization of electrical costs for traction-type elevators

This work examines the real-time utilization of energy in an operating elevator drive system with a goal, not of improving efficiency per se, but rather of reducing the cost paid by the system owner for the operation of the equipment. Several load-leveling and peak-shaving schemes using ultracapacitors are reviewed, including (1) off-peak energy storage for on-peak use, (2) energy storage to reduce the utility demand cost, (3) energy storage to reduce inrush peaks, and (4) energy storage to redirect regenerated energy. Each of these schemes is developed to demonstrate technical acceptability and then evaluated with respect to cost effectiveness.