Door operating arrangement in an elevator

Abstract

A door operating arrangement in an elevator, including a door operating unit located in the elevator car including a door controller and a door drive as well as a door motor configured to open and close elevator car doors, optionally together with elevator landing doors, a DC bus connecting the door operating unit via a travelling cable of the elevator car with a DC power source of the elevator. The voltage level of the DC bus is between 40 V and 120 V, the DC bus is connected to a capacitor bank located in the elevator car having a parallel connection of at least two capacitors and a total capacity value of at least 75.000 μF, preferably at least 100.000 μF.

Claims

1. A door operating arrangement in an elevator, comprising: a door operating unit located in an elevator car of the elevator, the door operating unit including: a door controller; a door motor configured to open and close car doors of the elevator car, the door motor being an AC motor with an operating range of 18V to 60V; and a door drive, wherein the door drive comprises an inverter bridge connected with phases of the door motor, the inverter bridge being controlled by the door controller; a DC bus directly electrically connected to the door drive to connect the door operating unit with a DC power source of the elevator, the DC bus running in a travelling cable of the elevator car; a DC module; and a capacitor bank connected directly between the DC module and the door operating unit and provided in the elevator car, the capacitor bank having a parallel connection of at least two capacitors and a total capacity value of at least 75,000 μF, wherein the voltage level of the DC bus is more than 40 V, and wherein the DC bus is connected to the capacitor bank.

2. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 40V and 120 V.

3. The door operating arrangement according to claim 1, wherein the distance from the capacitor bank to the door operating unit is no longer than 1 m.

4. The door operating arrangement according to claim 1, wherein the capacitor bank is located on a same circuit board as the door drive.

5. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 40 V and 60 V.

6. The door operating arrangement according to claim 1, wherein the capacity value of the capacitor bank is between 100.000 μF and 300,000 μF.

7. The door operating arrangement according to claim 1, wherein the DC power source is a DC link of a frequency converter of a motor drive of the elevator.

8. The door operating arrangement according to claim 1, wherein the DC module is fixed in a building and comprises a DC converter converting the voltage of the DC power source on a primary side thereof to a DC voltage on a secondary side thereof between 40V and 120 V.

9. The door operating arrangement according to claim 8, wherein the DC converter is at the secondary side connected to a smoothing circuit.

10. The door operating arrangement according to claim 1, wherein the door controller comprises a rescue circuit for operating the elevator car door and optionally the landing doors in abnormal operating situations via a switch located in connection with the elevator car and/or the elevator control panel.

11. An elevator comprising the door arrangement according to claim 1.

12. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 50V and 120 V.

13. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 55V and 120 V.

14. The door operating arrangement according to claim 1, wherein the distance from the capacitor bank to the door operating unit is no longer than 50 cm.

15. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 50 V and 60 V.

16. The door operating arrangement according to claim 1, wherein the voltage level of the DC bus is between 55 V and 60 V.

17. The door operating arrangement according to claim 1, wherein the capacity value of the capacitor bank is between 120,000 and 200,000 μF.

18. The door operating arrangement according to claim 1, wherein the DC module is fixed in a building and comprises a DC converter converting the voltage of the DC power source on a primary side thereof to a DC voltage on a secondary side thereof between 40V and 60 V.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will hereinafter be described in connection with the enclosed drawing.

(2) FIG. 1 is a schematic diagram of an inventive door operating arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) The inventive door operating arrangement 10 comprises a door operating unit 12 comprising a door drive 14, for example an inverter bridge, which door drive 14 is controlled by a door controller 16 and which door drive 14 is connected with the phases of a door motor 18 which is preferably an AC motor with an operating range of 18 to 60 V. Connected to the door operating unit 12 is a capacitor bank 20 comprising four capacitors 22 connected in parallel which capacitor bank has a total capacity value of at least 75.000 μF, preferably at least 100.000 μF, most preferably between 120.000 μF and 200.000 μF. This leaves enough energy for the operation of the door operating unit even a certain time after power off of the DC power source of the elevator. The capacitor bank 20 is connected to a DC bus 24 which is running in the travelling cable 26 of the elevator car where it is connected with a DC module 28 comprising a DC converter 30 to which the DC bus 26 is connected via a smoothing circuit 32. The smoothing circuit 32 comprises inductances and capacitors in a per se known arrangement to minimize any voltage ripple in the DC bus 24. The DC converter 30 of the DC module 28 is connected to a DC link 34 of the frequency converter of a motor drive 36 of the elevator.

(4) The voltage level in the DC bus 24 is preferably between 50 V and 60 V, most preferably between 55 V and 60 V. 60 V forms for a DC voltage a kind of safety barrier above which additional safety measures have to be taken which again make the solution more expensive. On the other hand, the voltage in the DC bus should go as near to this limit value of 60 V as possible as the power stored in the capacitor bank 20 is characterized by a product of the total capacity value with the square of the voltage in the DC bus. The DC link 34 in the frequency converter of the motor drive 36 has usually a DC voltage level of several hundred volts which is converted by the DC converter 30 to the above-mentioned appropriate level of 40 to 60 V, preferably 50 to 60 V, most preferably 55 to 60 V.

(5) During normal operation, the advantage of the present invention is that the peak power of the door operating unit 12 when the motor 18 is started to run can be supplied by the capacitor bank. This results in the fact that the current drawn from the DC power source, i.e. the DC link 34, does not show any high peaks which make the control of the DC power consumption difficult. On the other hand, this solution has the advantage that in case of mains power off, when no DC voltage can be provided by the DC link 34, the power stored in the capacitor bank is high enough to enable one door operation to open the elevator car doors as well as the landing doors after a rescue drive. Thus, the invention enables an automatic releasing of trapped passengers after a power fault of the AC mains.

(6) One advantage of the invention is that capacitor bank endures much more charging/discharging cycles than for example a battery. Therefore an increased lifetime may be achieved compared to a battery implementation.

(7) The above-mentioned embodiments do not restrict the scope of protection of the invention as apparent from the appended patent claims. It is to be mentioned that the smoothing circuit 32 between the DC converter 30 and the travelling cable 26 is optional and not necessary to carry out the invention. It is further necessary to mention that the capacitor bank does not need four parallel capacitors as mentioned in the figures but even one single capacitor may be sufficient to provide the necessary capacity value but for practical reasons it is better to provide the necessary total capacity by a parallel connection of several capacitors which saves space and which is also more economical than one super-capacitor which is comparably expensive. Anyway, the invention can also be realized with one super-capacitor having a capacity value of more than 70.000 μF.

LIST OF REFERENCE NUMBERS

(8) 10 door operating arrangement 12 door operating unit 14 door drive 16 door controller 18 door motor 20 capacitor bank 22 capacitors 24 DC bus 26 traveling cable of the elevator car 28 DC module 30 DC converter 32 smoothing circuit 34 DC link of the motor drive of the elevator motor—DC power source of the elevator 36 motor drive