Electrical power system with power limiting to network

• US 8,714,313 B2
• Filed: 07/25/2012
• Issued: 05/06/2014
• Est. Priority Date: 02/10/2010
• Status: Active Grant

• Current Assignee: Kone Corporation
• Original Assignee: Kone Corporation
• Inventors: Harkonen, Ari, Kallioniemi, Antti
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US13/557,638
• Publication Number:
  US 20120285774A1
• Time in Patent Office: 650 Days
• Field of Search: 187/247, 187/248, 187290-293, 187/296, 187/297, 187391-393, 318/375, 318/376, 318/380
• US Class Current: 187/289
• CPC Class Codes: B66B 1/302 for energy saving
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 2310/58 The condition being electrical
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

The invention relates to an electrical power system for operating elevators. The electrical power system includes: an electricity distribution network of a building, which includes an interface to a public electricity network; a plurality of hoisting machines of an elevator, each of which hoisting machines of an elevator is equipped to move an elevator car in an elevator hoistway; and also a power supply system, which includes an interface to the aforementioned hoisting machines of the elevator, and which power supply system includes an interface to the electricity distribution network of the building, for supplying power between the hoisting machines of the elevator and the electricity distribution network of the building.

Claims

1. An electrical power system for operating elevators, the electrical power system comprising:

a plurality of hoisting machines of an elevator, each of the plurality of hoisting machines moving an elevator car in an elevator hoistway; and

a power supply system that interfaces with an electricity distribution network of a building to transfer power between the plurality of hoisting machines and the electricity distribution network, the power supply system including a control apparatus that determines a power-handling capacity of the electricity distribution network available to the elevators;

wherein

the power supply system limits a net power flowing from the plurality of hoisting machines to the electricity distribution network to a limit value for net power determined based on the power-handling capacity of the electricity distribution network available to the elevators, and

the electricity distribution network of the building provides power to loads external to the elevator system.

2. The electrical power system according to claim 1, wherein the control apparatus determines the limit value for net power based on the net power flowing between the power supply system and the electricity distribution network.

3. The electrical power system according to claim 1, wherein the power supply system further comprises:

a plurality of power resistors; and

a plurality of controllable brake choppers;

wherein

each of the plurality of controllable brake choppers supplies electricity via the plurality of power resistors, and

the plurality of brake choppers consume a portion of the net power that flows from the plurality of hoisting machines of the elevator to the power supply system and that exceeds the limit value as heat in the power resistors.

4. The electrical power system according to claim 1, wherein the control apparatus comprises:

a voltage measurement device that measures a voltage of the electricity distribution network;

wherein

the control apparatus determines the power-handling capacity of the electricity distribution network available to the elevators based on the measured voltage of the electricity distribution network.

5. The electrical power system according to claim 4, wherein the power supply system limits a net power flowing from the power supply system to the electricity distribution network based on an increase in the voltage of the electricity distribution network.

6. The electrical power system according to claim 4, wherein the power supply system limits a net power flowing from the electricity distribution network to the power supply system based on a decrease in the voltage of the electricity distribution network.

7. The electrical power system according to claim 1, wherein the power supply system comprises:

a plurality of temporary storages of energy;

wherein

the power supply system supplies, to the plurality of temporary storages of energy, a portion of the power that flows from the plurality of hoisting machines of the elevator to the power supply system and that exceeds the limit value for net power.

8. The electrical power system according to claim 7, wherein the power supply system supplies, from the plurality of temporary storages of energy, the portion of the power that flows from the power supply system to the hoisting machines of the elevator and that exceeds the limit value for net power.

9. The electrical power system according to claim 1, wherein the power supply system comprises:

a plurality of power supply devices, each of the power supply devices interfacing with the electricity distribution network to transfer power between a corresponding hoisting machine and the electricity distribution network.

10. The electrical power system according to claim 9, wherein each of the plurality of power supply devices comprises:

a power resistor; and

a controllable brake chopper that supplies electricity via the power resistor;

wherein

the power supply device controls the brake chopper, such that the brake chopper consumes, as heat in the power resistor, a portion of the power that flows from a hoisting machine of the elevator to the power supply device and that exceeds the limit value for power supply applicable to the power supply device.

11. The electrical power system according to claim 9, wherein each of the plurality of power supply devices comprises:

a temporary storage of energy;

a controllable solid-state switch that adjusts the power flow of the temporary storage of energy;

wherein

the power supply device controls the solid-state switch to supply, at least one of to and from the temporary storage of energy, the portion of the power that flows between a hoisting machine of an elevator and a power supply device and that exceeds the limit value for power supply applicable to the power supply device.

12. The electrical power system according to claim 9, wherein each of the plurality of power supply devices is a frequency converter including a network inverter rectifier.

13. The electrical power system according to claim 9, wherein the control apparatus comprises:

a control unit connected to the plurality of power supply devices;

wherein

the control unit determines the power-handling capacity of the electricity distribution network available to the elevators,

the control unit determines the limit value for net power flowing via the first interface based on the power-handling capacity,

the control unit sets, for each of the plurality of power supply devices, a limit value for power supply such that the limit values for the power supply of the different power supply devices in total are less than the limit value for net power,

the control unit notifies each of the plurality of power supply devices of the limit value for an applicable power supply, and

each of the plurality of power supply devices limits the power flow between the electricity distribution network and a hoisting machine to the notified limit value for power supply determined by the control unit for that power supply device.

14. The electrical power system according to claim 13, wherein the control unit determines, for each of the plurality of power supply devices, an individual limit value for power supply, and wherein the control unit notifies each of the plurality of power supply devices of the individual limit value for power supply applicable to that power supply device.

15. The electrical power system according to claim 13, wherein the control unit is in the control center of the elevators.

16. The electrical power system according to claim 1, wherein the power supply system comprises:

a plurality of power supply devices, each of the plurality of power supply devices interfacing with the electricity distribution network to transfer power between a corresponding hoisting machine of the elevator and the electricity distribution network, wherein

each of the plurality of power supply devices determines the power-handling capacity of the electricity distribution network available to the elevators, and

each of the plurality of power supply devices determines the limit value for net power flowing via the first interface based on the power-handling capacity of the electricity distribution network available to the elevators.

17. The electrical power system according to claim 1, wherein the control apparatus is connected to a building automation system, and wherein the building automation system communicates information about the degree of loading of the electricity distribution network to the control apparatus via the connection between the control apparatus and the building automation system.

18. The electrical power system according to claim 1, wherein the electricity distribution network is connected to loads that are external to the elevator.

19. The electrical power system according to claim 1, wherein the electricity distribution network is connected to a public electricity distribution network.

20. The electrical power system according to claim 19, wherein the power-handling capacity of the electricity distribution network available to the elevators is determined based on a limit value for maximum permitted power to be supplied between the public electricity network and the electricity distribution network as well as based on a net power consumption of loads to be connected to the electricity distribution network.

21. The electrical power system according to claim 19, wherein the electricity distribution network is connected to the public electricity network via a main board, and wherein fuses of the main board are configured to determine the limit value of the maximum permitted power to be supplied between the public electricity network and the electricity distribution network.

22. The electrical power system of claim 1, further comprising:

the electricity distribution network of the building that interfaces with a public electricity network.