A NEW APPROACH TO CONTROLLING A HYDRAULIC INDIRECT ELEVATOR WITH A VARIABLE‑SPEED PUMP

Abstract

The paper describes a new approach to the issue of controlling an indirect elevator with a bidirectional variable-speed pump and a simple controller based on the position sensor. The aim of this paper is to present a method of controlling the speed of the elevator to ensure smooth movement and proper positioning of the car on the floor, regardless of its load and ropes rigidity. The main feature of the proposed solution is the use of a frequency inverter in vector mode to control the speed of the car in both directions. The control function is based on virtual cams comparing actual measurements from the car position sensor. The proposed control strategy has been experimentally verified on the existing indirect elevator drive, and the obtained results indicate a very high accuracy in maintaining and shaping the speed and positioning of the car. The conducted research confirms the possibility of using a new method of controlling hydraulic and indirect elevators. The benefits of this method include a less complex hydraulic system, the control of overloads in the car and vibrations in the rope system, and the possibility of energy recovery.