Patent ID: 9481549
Filing Date: 2016-11-01
CPC Classification: B66B,H02J

Claim Text:
1. A regenerative electric power storage control system for elevators, comprising: a converter that converts alternating current (AC) electric power to direct current (DC) electric power; an inverter that converts the DC electric power to variable voltage and variable frequency AC electric power, to drive an electric motor that causes an elevator car to ascend and descend; an electrical energy storage device provided, via an electric power charge and discharge unit, across DC buses located between the converter and the inverter, the energy storage device storing, during a regenerative operation of the car, DC energy that is supplied from the DC buses, and supplying, during a motoring operation of the car, to the DC buses the stored DC energy; an electric power charge and discharge control unit that calculates electrical energy that is stored during the regenerative operation of the car in the energy storage device, and electrical energy that is supplied from the energy storage device to the DC buses during the motoring operation of the car, and then controls the electric power charge and discharge unit; an electric power charge and discharge control power supply that supplies DC electric power to the charge and discharge control unit; and voltage conversion unit that supplies the DC energy stored in the energy storage device to the charge and discharge control power supply, wherein the charge and discharge control unit calculates, on a time zone basis, electrical energy stored in and electrical energy discharged from the energy storage device during a predetermined period, and in a time zone where after the predetermined period, a value derived by subtracting the discharged electrical energy of the energy storage device from the stored electrical energy thereof is a predetermined value or greater, the charge and discharge control unit supplies the DC energy stored in the energy storage device to the DC buses via the electric power charge and discharge unit and to the charge and discharge control power supply via the voltage conversion unit.