Regenerative power control for VVVF motor drive (critical braking method applied to the elevator)

摘要

A method for braking induction motors is described. The method, called critical braking, consumes the regenerative power within the rotor and stator windings of the induction motor itself. Critical braking is realized by maintaining the induction motor slip at a constant value at which the regenerative power and the consumed power in the windings balance. A practical control system is described that applies this principle to a motor drive for elevator applications.