Fuzzy-Based Direct Power Control on Elevator System with Energy Feedback

In order to save the regenerated power energy and improve the power quality of the traditional variable voltage variable frequency (VVVF) elevator, a new energy feedback elevator system is presented in this chapter. The shunt converter is used here to offer a feedback path for the regenerative energy and to eliminate the harmonics. This chapter proposes a novel direct power control (DPC) based on fuzzy-logic to control the shunt-converter that is appending to the elevator. In terms of the instantaneous power theory, the novel DPC scheme regulates the instantaneous active and reactive power simultaneously by tracking the power errors. Without hysteresis comparators, the proper switching states of the converter are selected according to the fuzzy logic rules, in accordance with the input fuzzy variables and the voltage sector numbers. The simulation results verify that the regenerated energy could be fed back to the mains, and at the same time, sinusoidal grid current and unit power factor could be achieved. The new energy feedback elevator system has excellent steady and dynamic performance while the power quality is enhanced.