SYSTEM FOR RECOVERING THE BRAKING ENERGY OF AN ELEVATOR BY USING ULTRACAPACITORS

摘要

The present invention presents an improved-control system for recovering the braking energy on a permanent-magnet synchronous motor of elevators which is driven by a static power converter. The recovery of the braking energy is effected by means of ultracapacitors in which the braking energy is temporarily stored and then is provided when the machine of the elevator operates as a motor. The storage and recovery of the braking energy is effected by means of a DC/DC converter with bidirectional power flow which is directly connected to the DC-link of the static driving-power converter of the electric machine of the elevator (at the common connection node of the rectifier and the inverter of the power converter). The present invention achieves a reduction in the energy that the system of the elevator consumes from the grid and at the same time a reduction in the fluctuations in the current of the ultracapacitors. In this way, the total efficiency of the system of the elevator per operation cycle is increased, as well as the reliability and lifetime of the ultracapacitors. This is achieved by varying the voltage of the DC-link depending on the operation conditions of the elevator and taking into account only the current of the ultracapacitors.