EP2597061A1

EP2597061A1 - Energy saving system for direct current elevators

Info

Publication number: EP2597061A1
Application number: EP12192516.8A
Authority: EP
Inventors: David Palomares Ayerbe; Juan Manuel De Francisco Diez; Carlos Garrido Garcia; Fernando Arteche Gonzalez; Francisco Javier Piedrafita Orduna; Alfredo Gomez Espinosa; Jorge Luesma Pazos
Original assignee: Industrial de Elevacion SA; Instituto Tecnologico de Aragon
Current assignee: Industrial de Elevacion SA; Instituto Tecnologico de Aragon
Priority date: 2011-11-22
Filing date: 2012-11-14
Publication date: 2013-05-29
Also published as: ES2371847A1; ES2371847B1

Abstract

Energy saving system for direct current elevators, whose system can be connected to all kinds of frequency adjusters coupled to the motor of an elevator and which incorporates at least one source of power and one source of voltage; an energy storage device and an electronic control unit, with the purpose of storing the energy generated by braking, said system comprising a first DC/DC converter (6), which operates as the energy current charger; an energy storage means (7); a second DC/DC converter (8) which transfers the stored energy to the auxiliary elements (9), and an electronic energy flow control unit (10), so that the first DC/DC converter (6) and the second DC/DC converter (8) operate in series and all the energy generated by braking the elevator is stored in the storage means (7) for its subsequent use by the auxiliary elements (9).

Description

OBJECT OF THE INVENTION

The present invention, as expressed in the wording of the present specification, relates to an energy saving system for direct current elevators, whose system can be connected to all kinds of frequency adjusters coupled to the motor of an elevator, whose main object is the storage of all the energy generated by braking to feed the different auxiliary elements only, in other words, by acting as an energy "buffer".
Therefore, the energy saving system object of the invention supplies energy only to the auxiliary elements of the elevator, delaying the entry of these elements into a "stand-by" state, so that the auxiliary elements are subjected to a smaller number of on/off cycles, therefore extending their useful life.
Likewise, since the auxiliary elements use less network energy, it represents significant energy saving.

FIELD OF APPLICATION

The present specification describes an energy savings system for direct current elevators, which is specifically applied to the connection to all kinds of frequency adjusters coupled to the drive motor of elevators.

BACKGROUND OF THE INVENTION

Over time, the technology related to elevating devices, such as elevators, have experienced important progress with the purpose of providing users with greater comfort and security.
Thus, elevators had been using two-speed motors without frequency adjusters, so that, even though they fulfilled their function appropriately, the variation in the acceleration and braking speeds could be perceived and they lacked precision when stopping.
Frequency adjusters were subsequently incorporated with the purpose of improving the features, in order to allow continuous acceleration and braking speeds without abrupt changes, and to improve the precision of the stops, as well as other features, such as increasing their life and establishing energy savings.
On the other hand, it is known that the energy generated when the elevator brakes is dissipated by the frequency adjuster by means of the braking resistance.
This way, one of the purposes of the invention is to save energy, so that, by means of the use of regenerative adjusters, the energy generated during braking is returned to the network, without contributing any economic advantage to the owner.
On the other hand, with this objective in mind, we can consider different documents such as EP 2336068 , which describes an "energy management system for electric motors", whose system presents a configuration consisting on a DC/DC converter and another parallel DC/AC converter, so that AC energy is used to feed the elevator and the related auxiliary elements. The braking energy present at the direct current bus can then be used to feed the energy storage means and/or the auxiliary elements. In turn, the energy of the storage means can feed both the motor and the auxiliary elements. In addition, the system uses an element in the form of a switch prior to the auxiliary elements, which allows feeding these from the network or from the energy storage means. Likewise, there would be a need to incorporate a transformer between the DC/AC converter and the auxiliary elements to be fed.
Other documents related to the object of the invention that could be taken into account are WO 2010019126 and WO 2010019122 , so that WO 2010019126 describes a "method for the energy management of an elevating system", provided with a primary network energy supply and a stored energy level detection system with a controller, so that the contribution of energy would come from the network, the storage system or a combination thereof, while WO 2010019122 describes an "energy and current line storage controller for an elevator motor", by means of which the intensities of the network and the storage system, as well as the energy storage level and the demand for intensity of the motor, are controlled.
Likewise, we can consider documents ES 2317890 and ES 2320094 , so that ES 2317890 describes a "device and procedure to reduce the power of the network connection of elevator facilities", which incorporates supercapacitors as storage means for the energy originating from the braking of the elevator and whose stored energy is used to minimize the peaks of energy produced during the startup of the elevator, while document ES 2320094 describes a "emergency supply device for elevator facilities", which have an energy storage means provided with energy from the network or from the braking, which also serves as energy source in normal conditions to mitigate power peaks during startup.

DESCRIPTION OF THE INVENTION

The present specification describes an energy savings system for direct current elevators, whose system can be connected to all kinds of frequency adjusters coupled to the motor of an elevator and which incorporates:

at least one source of power and one source of voltage;
an energy storage device, and;
an electronic control unit;

a first DC/DC converter which operates as an energy current charger;
at least one energy storage means;
a second DC/DC converter which transfers the stored energy to the auxiliary elements by adapting their operating voltage to the operating voltage of the energy storage means, and;
an electronic energy flow control unit based on the state of each one of the components of the energy saving system and the parameters coordinated with the elevator's "stand-by".

The electronic control unit is bidirectionally communicated to the elevator's control electronics for the control of the "stand-by" state of the different auxiliary elements to be fed.
In addition, the electronic control unit is also connected to the DC/DC converters, allowing it to supervise and adjust the input and output voltage of the energy storage means.
In a preferred embodiment of the invention, the energy storage means is defined by at least one supercapacitor.
Likewise, in another variation of the embodiment of the invention, the energy storage means can be based on at least one battery.
Next, in order to supplement the description to be made below and with the purpose of helping a better comprehension of the characteristics of the invention, a set of drawings, whose single figure represents the most characteristic details of the invention in an illustrative rather than limitative manner, accompany this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1. Shows a schematic view of a block diagram of the energy saving system for direct current elevators.

DESCRIPTION OF A PREFERRED EMBODIMENT

In view of the aforementioned figures and according to the numerical references used, we can observe how the energy saving system for direct current elevators is based on a conventional structure in which a frequency adjuster 2 has been coupled to an elevator motor 1, said frequency adjuster 2 presenting a rectifier 3 and an inverter 4, being fed from the general electric network 5 and incorporating the corresponding brake resistance.
Based on this generic structure, the energy saving system for direct current elevators object of the invention is incorporated, whose system is constituted by a first DC/DC converter 6 which operates as an energy current charger for a storage means 7, and a second DC/DC converter 8 which transfers the energy stored in the storage means 7 to the auxiliary elements 9 of the elevator by adapting the operating voltage of the auxiliary elements 9 to the operating voltage of the energy storage means 7.
On the other hand, the system incorporates an electronic energy flow control unit 10 based both on the state of each of the components of the energy saving system and on the parameters coordinated with the elevator's "stand-by". Therefore, the electronic energy flow control unit 10 is communicated to the elevator's control electronics 11.
One of the characteristics of the system is that the first DC/DC converter 6 and the second DC/DC converter 8 operate in series, working in direct current, and all the energy generated by braking the elevator is stored in the storage means 7 for its subsequent use by the auxiliary elements 9 only.
This way, the energy saving system does not need to use a transformer, thus reducing costs and simplifying its topology.
Therefore, it could be said that the system operates as an energy "buffer" because it stores all the energy generated by the elevator's braking in the storage means 7 and distributes it to the auxiliary elements 9 as needed.
In a preferred embodiment of the invention, the energy storage means is based on at least one supercapacitor 7. In addition, the electronic energy flow control unit 10 is connected to the DC/DC converters with the purpose of controlling the load of the energy storage means and acting based on this load.
This way, the electronic energy flow control unit 10 limits the intensity and the maximum load voltage of the storage means 7, stopping the load when the upper limit is reached, and starting the load when there is input voltage available and the voltage of the storage means 7 is low.
In another embodiment of the invention, the storage means 7 can be based on, at least, one battery.
The energy saving system for direct current elevators object of the present invention allows the use of any frequency adjuster model without needing to modify it.
In conclusion, the essential characteristics of the system are the following: it operates in direct current and all the energy generated by the elevator's braking is stored to be used thereafter only by the auxiliary elements of the elevator itself.

Claims

Energy saving system for direct current elevators, whose system can be connected to all kinds of frequency adjusters coupled to the motor of an elevator and which incorporates:
- at least one source of current and one source of voltage;

- an energy storage means, and;

- an electronic control unit;
with the purpose of storing the energy generated by braking, so that the system is characterized in that it comprises:
• a first DC/DC converter (6) which operates as an energy current charger;

• at least one energy storage means (7);

• a second DC/DC converter (8) which transfers the stored energy to the auxiliary elements (9) by adapting the operating voltage of the auxiliary elements (9) to the operating voltage of the energy storage means (7), and;

• an electronic energy flow control unit (10) based both on the state of each one of the components of the energy saving means and on the parameters coordinated with the elevator's "stand-by";
so that the first DC/DC converter (6) and the second DC/DC converter (8) operate in series and all the energy generated by braking the elevator is stored in the storage means (7) for its subsequent use by the auxiliary elements (9).
Energy saving system for direct current elevators according to claim 1, characterized in that the electronic energy flow control unit (10) is bidirectionally communicated to the elevator's control electronics (11) for the control of the "stand-by" state of the auxiliary elements (9).
Energy saving system for direct current elevators according to claim 1, characterized in that the storage means (7) is, at least one supercapacitor.