Computational simulation and experimental research on speed control of VVVF hydraulic elevator

This paper discusses and analyses the speed control of variable voltage variable frequency (VVVF) hydraulic elevator. The computational models of the control system are established. Numerical simulations are carried out with the SIMULINK of MATLAB. PID control law is adopted in experiments because the PID control algorithm is simple in operation, and is characteristic of good computer real-time control. It also possesses good adaptability when the parameters of the controlled object are changed. Experiments are also carried out for the upward and downward running speed of the VVVF hydraulic elevator. Computational simulations coincide with experimental results in general. The results of both simulations and experiments show that serious flutter occurs at the start-up of the VVVF hydraulic elevator, and there is an oscillating phenomenon in the system. During the start-up of the VVVF hydraulic elevator, the system absorbs elastic energy when static friction is changed to dynamic friction. This results in the oscillations after starting. (C) 2003 Elsevier Ltd. All rights reserved.