Energy recovery control in elevators with automatic rescue application

Abstract

Efficiency enhancement and energy consumption reduction without performance degradation are becoming key issues in vertical transport systems. To achieve notable energy savings, modern Energy Management Systems (EMS) can play a significant role in this field. This work focuses on implementing an energy recovery system (ERS) for elevator systems deployment. In the proposed system, the dc link of the regenerative motor drive is connected to an energy storage device through a dc/dc power converter. The proposed control strategy utilizes the reverse power flow to accumulate energy on the storage device, that will be later utilized during lifting trips. Excess recovered energy is injected to the grid. The storage device is controlled to maintain a minimum energy level for emergency situations, to safely guarantee landing of the elevator's cart. Load sharing principles are utilized to minimize the apparent power ratings of the elevator apparatus. The electrical and mechanical models of the proposed systems are introduced, and a MATLAB simulation model is built to verify the proposed control strategy and to show the feasibility of the solution.