An efficient architecture for energy recovery in hydraulic elevators

Abstract

This study introduces an efficient architecture for hydraulically counter-weighting an elevator system while controlling for cab speed. A physical model of the architecture is developed and posed as a single-input single-output system in which the ratio of two hydraulic pump/motor swash plate angles serve as the control input for regulating the output cab speed. Heuristic control rules based on efficiency considerations and elevator operation are posed for the swash plate angles. A high-fidelity simulation tool is then employed to assess the new architecture and control approach. Simulations demonstrate the effectiveness of the devised control strategy and the overall satisfactory operation of the elevator system. Simulations also provide comparisons of the new architecture’s efficiency vs. an electrohydraulic elevator architecture employing a motor/generator for energy capture and return. It’s shown that the introduced architecture yields up to a 13% increase in actuation efficiency over the electrohydra...