Multi-drive system for regenerative energy management in elevator installations
By managing elevator regenerative energy through a variable frequency drive in a multi-drive system, the waste and additional costs of regenerative energy management in existing technologies are solved, achieving efficient energy utilization and adaptive management.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- OTIS ELEVATOR CO
- Filing Date
- 2022-11-21
- Publication Date
- 2026-05-29
AI Technical Summary
Existing elevator systems, when utilizing regenerative power, suffer from waste and additional costs due to energy management methods that require consumption or storage, especially by adding large resistive loads to absorb excess energy.
The system employs a multi-drive system, including first and second frequency converters. The first frequency converter supplies power to the elevator machinery under a first operating condition and receives regenerative energy under a second operating condition. The second frequency converter selectively receives and manages the regenerative energy, storing or dissipating it through an energy receiving device.
It enables efficient management of regenerative energy, reduces additional load costs, improves energy utilization efficiency, adapts to the power requirements of different elevator systems, and avoids unnecessary energy waste.
Smart Images
Figure CN117645226B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an elevator energy management system, and more particularly to a multi-drive system for regenerative energy management in elevator equipment. Background Technology
[0002] An elevator system typically consists of a car that moves vertically between different floors in a building. In some cases, the elevator mechanism consumes electrical power to propel the elevator car. Sometimes gravity can be used to achieve the desired movement of the elevator car, and the elevator mechanism can operate as a generator to provide regenerative electrical power.
[0003] While regenerative power is desirable for reducing energy consumption, the energy gained must be either consumed or stored. One approach involves adding large resistor loads to the power line to absorb the excess energy. Adding such resistors introduces additional cost and results in absorbing more energy than needed, which is considered wasteful. Summary of the Invention
[0004] An illustrative exemplary embodiment of an elevator energy management system includes a first variable frequency drive (VFD) configured to deliver electrical power from a power source to elevator machinery during a first operating condition and to receive regenerative energy from the elevator machinery during a second operating condition. A second VFD is configured to selectively receive regenerative energy from the first VFD during the second operating condition. At least one energy receiving device is coupled to the second VFD. The energy receiving device is configured to receive regenerative energy from the second VFD.
[0005] In addition to one or more of the features described above, or as an alternative, the second frequency converter is configured to communicate with the first frequency converter to receive an indication of the amount of regenerative energy received by the first frequency converter or the amount of regenerative energy to be received by the second frequency converter during at least the second operating condition.
[0006] In addition to one or more of the features described above, or as an alternative, the amount of regenerative energy to be received by the second frequency converter is less than the amount of regenerative energy received by the first frequency converter.
[0007] In addition to one or more of the features described above, or as an alternative, the second frequency converter controls the amount of regenerative power received by the second frequency converter based on an indication of the amount of regenerative energy to be received by the second frequency converter.
[0008] In addition to one or more of the features described above, or as an alternative, the second frequency converter is configured to determine the amount of regenerative energy to be received from the first frequency converter during the second operating conditions.
[0009] In addition to one or more of the features described above, or as an alternative, at least one energy receiving device includes an energy storage device configured to receive regenerated energy from a second frequency converter.
[0010] In addition to one or more of the features described above, or as an alternative, the energy storage device includes a battery.
[0011] In addition to one or more of the features described above, or as an alternative, the energy storage device includes a flywheel.
[0012] In addition to one or more of the features described above, or as an alternative, at least one energy receiving device includes at least one energy dissipation component.
[0013] In addition to one or more of the features described above, or as an alternative, at least one energy dissipation component includes a resistive load.
[0014] An illustrative exemplary embodiment of a method for managing energy in an elevator system includes: during a first operating condition, delivering electrical power from a power source to elevator machinery via a first frequency converter; during a second operating condition, receiving regenerated energy from the elevator machinery at the first frequency converter; during the second operating condition, receiving at least some of the regenerated energy from the first frequency converter at a second frequency converter; and delivering the regenerated energy received by the second frequency converter to at least one energy receiving device coupled to the second frequency converter.
[0015] In addition to one or more of the features described above, or as an alternative, the method includes communicating between a first frequency converter and a second frequency converter to provide the second frequency converter with an indication of the amount of regenerative energy received by the first frequency converter or the amount of regenerative energy to be received by the second frequency converter during at least a second operating condition.
[0016] In addition to one or more of the features described above, or as an alternative, the method includes controlling the amount of regenerative energy received by the second frequency converter to be less than the amount of regenerative energy received by the first frequency converter.
[0017] In addition to one or more of the features described above, or as an alternative, the method includes controlling the amount of regenerative power received by the second frequency converter based on an indication of the amount of regenerative energy to be received by the second frequency converter.
[0018] In addition to one or more of the features described above, or as an alternative, the second frequency converter determines the amount of regenerative energy to be received by the second frequency converter from the first frequency converter during the second operating conditions.
[0019] In addition to one or more of the features described above, or as an alternative, at least one energy receiving device includes an energy storage device configured to receive regenerated energy from a second frequency converter.
[0020] In addition to one or more of the features described above, or as an alternative, the energy storage device includes a battery.
[0021] In addition to one or more of the features described above, or as an alternative, the energy storage device includes a flywheel.
[0022] In addition to one or more of the features described above, or as an alternative, at least one energy receiving device includes at least one energy dissipation component.
[0023] In addition to one or more of the features described above, or as an alternative, at least one energy dissipation component includes a resistive load.
[0024] From the following detailed description, various features and advantages of at least one disclosed exemplary embodiment will become apparent to those skilled in the art. The accompanying drawings, accompanying the detailed description, can be briefly described below. Attached Figure Description
[0025] Figure 1 A schematic diagram of selected portions of an exemplary elevator system.
[0026] Figure 2 An exemplary embodiment of a multi-driver system is schematically illustrated.
[0027] Figure 3 It is a flowchart or diagram that summarizes an exemplary energy management process. Detailed Implementation
[0028] Figure 1 Selected portions of an elevator system 20 are schematically illustrated. An elevator car 22 moves vertically within a shaft 24. In the illustrated exemplary embodiment, a counterweight 26 is connected to the elevator car 22 via an elevator rope 28, which may include, for example, a round rope or a flat belt. Although a traction-driven elevator system is shown for purposes of discussion, specific configurations of the elevator system 20 may differ from those shown.
[0029] Elevator mechanism 30 controls the movement of elevator car 22. Mechanism 30 includes a motor to propel elevator car 22 as needed. Mechanism 30 also includes a brake to hold elevator car 22 in selected positions, such as at a floor where passengers expect to enter or leave elevator car 22.
[0030] The first frequency converter 32 is configured to supply electrical power to the elevator machinery 30 during a first operating condition in which the motor of the machinery 30 requires power to move the elevator car 22. The first frequency converter 32 is also configured to receive regenerative energy from the elevator machinery 30 during a second operating condition in which the motor of the machinery 30 generates regenerative energy.
[0031] For example, the second operating condition occurs during the movement of the elevator car 22 due to gravity. One such exemplary second operating condition involves moving the elevator car upward when it is empty. Under this condition, gravity pulls the counterweight 26 downward, causing the elevator car 22 to move upward because the mass of the counterweight 26 is greater than the mass of the empty elevator car 22. In the second operating condition of moving the elevator car 22 using gravity, the motor of the elevator mechanism 30 functions as a generator to produce regenerative energy. Another exemplary second operating condition occurs when the elevator decelerates and the motor regenerates power due to system mass and inertia. The first variable frequency drive 32 receives such regenerative energy from the elevator mechanism 30 and is configured to deliver it to the associated power grid, so that it can be used, for example, to provide power to other loads.
[0032] The second frequency converter 34 is configured to selectively receive at least some of the regenerated energy from the first frequency converter 32 during a second operating condition. The second operating driver 34 is configured to deliver the regenerated energy to at least one energy receiving device 36 electrically connected to the second frequency converter 34, such as via conventional wiring.
[0033] Figure 2 The exemplary configurations of a first frequency converter 32 and a second frequency converter 34 are schematically illustrated. In this exemplary embodiment, the second frequency converter 34 has the same components and arrangement as the first frequency converter 32. The exemplary second frequency converter 34 is capable of bidirectional energy reception and transmission. In other embodiments, the second frequency converter is configured for unidirectional energy reception and transmission. Specific components within the second frequency converter 34 may be varied to meet the needs of a particular installation.
[0034] like Figure 2 As shown, a power source 38 (such as a public power grid or a local uninterruptible power supply) provides electrical power, which is delivered by a first frequency converter 32 to the motor of the elevator mechanism 30 during a first operating condition, which is when electrical power is needed to move the elevator car 22. In some embodiments, the power source 38 provides three-phase electrical power. During a second operating condition (such as the second operating condition mentioned above) in which the first frequency converter 32 receives regenerative energy from the elevator mechanism 30, Figure 2 The system shown is configured to manage such energy in an efficient and economical manner.
[0035] The second frequency converter 34 selectively receives at least some of the regenerated energy from the first frequency converter 32. The second frequency converter 34 then delivers the received regenerated energy to the energy receiving device 36. Figure 2 In the example, energy receiving device 36 includes at least one energy dissipation component (such as a resistor) to absorb excess regenerative energy in the system. Other configurations of energy receiving device 36 are included in other embodiments. For example, instead of a three-phase load as schematically shown in the figures, energy receiving device 36 may be a single component connected to two of the output phases of the second driver 34 or a component connected between one of the output phases and the DC bus.
[0036] In another exemplary embodiment, the energy receiving device 36 has energy storage capacity and includes a rechargeable battery, flywheel, or supercapacitor. In such an embodiment, the second frequency converter 34 is configured for bidirectional power flow. The energy stored by the energy receiving device 36 can be supplied to other parts of the power grid, including the first frequency converter 32 or other parts of the elevator system 20, as appropriate, via the second frequency converter 34.
[0037] The amount of regenerated energy received by the second frequency converter 34 and delivered to the energy receiving device 36 can be selectively controlled to achieve the desired power balance throughout the system. Some of the regenerated energy received by the first frequency converter 32 can be fed back to the power source 38 when appropriate. For example, when the power source 38 is a public power grid capable of receiving energy, at least some of the regenerated energy can be delivered to the power source 38. Figure 2 Another load 40, schematically shown, may receive and utilize at least some of the regenerated energy. Load 40 may be another device that is part of elevator system 20, another elevator, or a device located at or near the site of elevator system 20, such as a lighting or building climate control system. Load 40 may utilize some of the regenerated energy, store such energy, or absorb it, depending on the configuration of load 40.
[0038] The first frequency converter 32, the second frequency converter 34, or both include control logic, an application-specific integrated circuit (ASIC), or a processor for selectively controlling the amount of regenerative energy received by the second frequency converter 34. In one exemplary embodiment, the first frequency converter 32 tracks or measures the regenerative power received by the first frequency converter 32 and communicates with the second frequency converter 34 to provide an indication to the second frequency converter 34 of receiving regenerative power. In some such embodiments, the second frequency converter 34 responds to the first frequency converter 32 and receives regenerative energy until the first frequency converter 32 provides an indication to stop receiving such energy. In other exemplary embodiments, the second frequency converter 34 is configured to determine when and how much regenerative energy to receive.
[0039] The second frequency converter 34 regulates the amount of regenerative energy absorbed within the system by the load 40, power source 38, or both. Real-time communication between the first frequency converter 32 and the second frequency converter 34 allows the management system to determine where the regenerative energy is delivered to adapt to various secondary operating conditions and different amounts of regenerative power generated by the motor of the elevator machinery 30.
[0040] For illustrative purposes, the above diagrams and illustrations depict a one-to-one relationship between the variable frequency drive and the elevator. Other embodiments include drives configured for group control. For example, an embodiment includes a second variable frequency drive 34 configured to receive energy from at least two elevators, which can simultaneously operate under a second operating condition. Alternatively, elevator group control may be included such that such a second variable frequency drive 34 receives regenerative energy from only one elevator at any given time.
[0041] For example, the disclosed exemplary embodiments and other embodiments like them adapt to a wide range of elevator system power requirements without requiring undesirable and expensive sets of resistive loads to absorb excess energy. During elevator installation and in cases where there is a minimal additional load to which regenerative energy can be channeled, an energy management system like the one described above efficiently adapts to regenerative energy. Controlling the second frequency converter 34 to selectively receive regenerative energy from the first frequency converter 32 flexibly and economically customizes how regenerative energy is processed within the system.
[0042] The various features of the disclosed exemplary embodiments are not necessarily limited to those embodiments. Other combinations of such features may implement additional or different embodiments.
[0043] The foregoing description is exemplary in nature and not restrictive. Variations and modifications to the disclosed examples will become apparent to those skilled in the art, and they do not necessarily depart from the spirit of the invention. The scope of legal protection afforded to the invention can be determined solely by reading the appended claims.
Claims
1. An elevator energy management system, comprising: A first frequency converter drive is configured to deliver electrical power from a power source to the elevator machinery during a first operating condition and to receive regenerative energy from the elevator machinery during a second operating condition. The second frequency converter is configured to selectively receive regenerative energy from the first frequency converter during the second operating condition. and At least one energy receiving device is connected to the second frequency converter drive, the at least one energy receiving device being configured to receive regenerated energy from the second frequency converter drive; The second frequency converter is configured to communicate with the first frequency converter to receive an indication of the amount of regenerative energy received by the first frequency converter or the amount of regenerative energy to be received by the second frequency converter at least during the second operating condition.
2. The elevator energy management system according to claim 1, wherein, The amount of regenerative energy received by the second frequency converter is less than the amount of regenerative energy received by the first frequency converter.
3. The elevator energy management system according to claim 1, wherein, The second frequency converter controls the amount of regenerative power received by the second frequency converter based on the indication of the amount of regenerative energy to be received by the second frequency converter.
4. The elevator energy management system according to claim 1, wherein, The second frequency converter is configured to determine the amount of regenerative energy to be received from the first frequency converter during the second operating condition.
5. The elevator energy management system according to claim 1, wherein, The at least one energy receiving device includes an energy storage device configured to receive regenerated energy from the second frequency converter.
6. The elevator energy management system according to claim 5, wherein, The energy storage device includes a battery or a flywheel.
7. The elevator energy management system according to claim 1, wherein, The at least one energy receiving device includes at least one energy dissipation component.
8. The elevator energy management system according to claim 7, wherein, The at least one energy dissipation component includes a resistive load.
9. The elevator energy management system according to claim 1, wherein, The second frequency converter is configured to selectively deliver electrical power to the first frequency converter.
10. A method for managing energy in an elevator system, the method comprising: During the first operating condition, electrical power is delivered from the power source to the elevator mechanism via the first frequency converter drive; During the second operating condition, regenerative energy is received from the elevator machinery at the first frequency converter drive; During the second operating condition, at least some of the regenerated energy is received from the first frequency converter at the second frequency converter drive; and The regenerative energy received by the second frequency converter is delivered to at least one energy receiving device connected to the second frequency converter. The method includes communicating between the first frequency converter and the second frequency converter to provide the second frequency converter with an indication of the amount of regenerative energy received by the first frequency converter or the amount of regenerative energy to be received by the second frequency converter at least during the second operating condition.
11. The method of claim 10, further comprising controlling the amount of regenerative energy received by the second frequency converter to be less than the amount of regenerative energy received by the first frequency converter.
12. The method of claim 10, further comprising controlling the amount of regenerative power received by the second frequency converter based on the indication of the amount of regenerative energy to be received by the second frequency converter.
13. The method according to claim 10, wherein, The second frequency converter determines the amount of regenerative energy to be received by the second frequency converter from the first frequency converter during the second operating condition.
14. The method of claim 10, wherein, The at least one energy receiving device includes an energy storage device configured to receive regenerated energy from the second frequency converter.
15. The method according to claim 14, wherein, The energy storage device includes a battery or a flywheel.
16. The method of claim 10, wherein, The at least one energy receiving device includes at least one energy dissipation component.
17. The method according to claim 16, wherein, The at least one energy dissipation component includes a resistive load.
18. The method of claim 10, further comprising selectively supplying electrical power to the first frequency converter via the second frequency converter driver.