Regenerative electric power storage control system for elevators

• US 9,481,549 B2
• Filed: 10/18/2011
• Issued: 11/01/2016
• Est. Priority Date: 10/18/2011
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Ishiguro, Hidetaka
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US14/348,714
• Publication Number:
  US 20140238782A1
• Time in Patent Office: 1,841 Days
• Field of Search: 187/289, 187/290, 187/396, 187/397, 187/391, 187/393, 318/375, 318/376, 318799-815, 307/66, 307/69, 320/128, 320/132, 320/134, 320/135, 320/136, 320/143, 320/144
• US Class Current: 1/1
• CPC Class Codes: B66B 1/302 for energy saving
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A regenerative electric power storage control system for elevators, including: a converter that converts AC electric power to DC electric power; an inverter that converts the DC electric power to the AC electric power, and drives an electric motor that ascends and descends a car; an electric power storage apparatus provided, via an electric power charge and discharge unit, across DC buses located between the converter and the inverter; an electric power charge and discharge control unit to which DC electric power is supplied from an electric power charge and discharge control power supply and that controls the charge and discharge unit. The charge and discharge control unit calculates on a time zone basis electrical energy stored in and electrical energy discharged from the energy storage apparatus during a predetermined period, and based on the calculation result, determines a discharge operation for each time zone posterior to the predetermined period.

Claims

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.

2. The regenerative electric power storage control system for elevators, of claim 1,

wherein in a time zone where the stored electrical energy is a threshold value or greater and where a value derived by subtracting the discharged electrical energy from the stored electrical energy is the predetermined value or greater, the charge and discharge control unit supplies the DC energy stored in the energy storage device to the DC buses and the electric power charge and discharge control power supply,

wherein in a time zone where the stored electrical energy is the threshold value or greater and where a value derived by subtracting the discharged electrical energy from the stored electrical energy is less than the predetermined value, the charge and discharge control unit supplies the DC energy stored in the energy storage device to the DC buses alone, out of the DC buses and the electric power charge and discharge control power supply, and

wherein in a time zone where the stored electrical energy is less than the threshold value, the charge and discharge control unit does not supply the DC energy stored in the energy storage device to any of the DC buses and the charge and discharge control power supply.

3. The regenerative electric power storage control system for elevators, of claim 2, wherein the threshold value is a value derived by adding to power consumption of the charge and discharge control power supply, electrical energy to be lost because of a conversion performed by the voltage conversion unit.

4. The regenerative electric power storage control system for elevators, of claim 2, wherein the predetermined value is a value derived by adding to power consumption of the charge and discharge control power supply, electrical energy to be lost because of a conversion performed by the voltage conversion unit.

5. The regenerative electric power storage control system for elevators, of claim 3, wherein the predetermined value is a value derived by adding to power consumption of the charge and discharge control power supply, electrical energy to be lost because of a conversion performed by the voltage conversion unit.

6. The regenerative electric power storage control system for elevators, of claim 1, wherein an electric double-layer capacitor is used for the energy storage device.

7. The regenerative electric power storage control

system for elevators, of claim 2, wherein an electric double-layer capacitor is used for the energy storage device.

8. The regenerative electric power storage control system for elevators, of claim 3, wherein an electric double-layer capacitor is used for the energy storage device.

9. The regenerative electric power storage control system for elevators, of claim 4, wherein an electric double-layer capacitor is used for the energy storage device.

10. The regenerative electric power storage control system for elevators, of claim 5, wherein an electric double-layer capacitor is used for the energy storage device.