MANAGEMENT OF POWER SOURCE VARIATIONS IN AN ELEVATOR DRIVE SYSTEM

• US 20100116595A1
• Filed: 08/31/2006
• Published: 05/13/2010
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Atalla, Mauro J., Kang, Pengju, Oggianu, Stella M., Marvin, Daryl J., Thornton, Robert K., Blasko, Vladimir
• Granted Patent: US 8,333,265 B2
• Time in Patent Office: Days
• US Class Current: 187/289
• CPC Class Codes: B66B 1/30 effective on driving gear , e.g. acting on power electronics, on inverter or rectifier controlled motor
• CPC Class Codes: B66B 1/308 with AC powered elevator drive
• CPC Class Codes: H02M 5/12 for conversion of voltage or current amplitude only

Abstract

A device (22) manages power source variations in an elevator system. The device includes a transformer (60) having a primary (62) and a secondary (64). An input of the elevator system is connected to the secondary (64). Tap switches (66a, 66b, 66c, 66d) are connected to the transformer (60) such that each tap switch is connected to a tap point (68a, 68b, 68c, 68d) on the transformer (60). A controller (54) operates the tap switches (66a, 66b, 66c, 66d) based on a sensed power source output to provide power on the secondary (64) within a tolerance band of the elevator system.

Claims

1. A device for managing power source variations in an elevator system, the device comprising:

a transformer including a primary and a secondary, wherein an input of the elevator system is connected to the secondary;

a plurality of tap switches connected to the transformer, wherein each tap switch is connected to one of a plurality of tap points on the transformer; and

a controller that operates the tap switches based on a sensed power source output to provide power on the secondary within a tolerance band of the elevator system.

2. The device of claim 1, wherein the controller comprises a voltage sensor for sensing voltage of the power source and providing a signal to the controller related to the sensed voltage.

3. The device of claim 1, wherein the controller operates the tap switches based on a comparison of the sensed power source output to an expected power source output.

4. The device of claim 1, and further comprising:

an over-current protection circuit that disconnects the elevator system from the secondary if the controller senses an over-current condition on the primary.

5. The device of claim 1, wherein the tap switches comprise devices selected from the group consisting of relays, field effect transistors (FETs), insulated gate bipolar transistors (IGBTs), gate turn-off (GTO) thyristors, integrated gate commutated thyristors (IGCTs), triacs, silicon controlled rectifiers (SCRs), and bipolar transistors.

6. The device of claim 1, wherein the secondary comprises a plurality of windings.

7. The device of claim 1, and further comprising:

a transient filter coupled to the secondary for suppressing voltage transients in the device.

8. A method for managing power source variations to provide regulated power to an elevator system, the method comprising:

monitoring a power source voltage;

determining whether the power source voltage is within a tolerance band of the elevator system; and

regulating the voltage provided to the elevator system in response to variations of the power source voltage from the tolerance band.

9. The method of claim 8, wherein determining whether the power source is within a tolerance band of the elevator system comprises comparing the monitored power source voltage to an expected power source voltage.

10. The method of claim 9, wherein regulating the voltage provided to the power system comprises adjusting the power source voltage to within the tolerance band of the expected power source voltage.

11. The method of claim 8, wherein regulating the voltage provided to the power system comprises selecting a transformer primary to secondary winding ratio as a function of variations of the power source voltage.

12. The method of claim 8, wherein the power source is connected to a transformer primary winding and the elevator system is connected to a transformer secondary winding, and wherein regulating the voltage provided to the power system comprises:

adjusting a connection of the power source to the transformer primary winding such that an output voltage provided on the secondary winding is within the tolerance band.

13. The method of claim 12, wherein adjusting a connection of the power source to the transformer primary winding comprises:

controlling a plurality of tap switches connected between the power source and the transformer primary winding, wherein each tap switch is connected to one of a plurality of tap points on the transformer primary winding.

14. The method of claim 8, and further comprising:

monitoring a power source current; and

disconnecting the elevator system from the transformer secondary winding if the current exceeds a threshold current.

15. An elevator power system comprising:

a power source;

a transformer including a primary and a secondary;

a plurality of tap switches, wherein each tap switch is connected to one of a plurality of tap points on the transformer; and

a controller that operates the tap switches based on a sensed power source output to provide power on the secondary within a tolerance of a load.

16. The elevator power system of claim 15, wherein the controller comprises a voltage sensor for sensing voltage of the power source and providing a signal to the controller related to the sensed voltage.

17. The elevator power system of claim 15, wherein the controller operates the tap switches based on a comparison of the sensed power source output to an expected power source output.

18. The elevator power system of claim 15, and further comprising:

an over-current protection circuit that disconnects the load from the secondary if the controller senses an over-current condition on the primary.

19. The elevator power system of claim 15, wherein the tap switches comprise devices selected from the group consisting of relays, field effect transistors (FETs), insulated gate bipolar transistors (IGBTs), gate turn-off (GTO) thyristors, integrated gate commutated thyristors (IGCTs), triacs, silicon controlled rectifiers (SCRs), and bipolar transistors.

20. The elevator power system of claim 15, wherein the secondary comprises a plurality of windings.

21. The elevator power system of claim 15, wherein the load comprises an elevator hoist motor.