Modular electric drive for ring cranes and ring crane equipped with it

Abstract

Modular electric drive for a ring crane (1), characterized in that the electric drive (15) comprises one or more electric current containers (16), where each electric current container (16) has an input (17) for AC power for connecting an AC source (18), one or more outputs (19) for DC power for connecting components (20) to be driven of the ring crane (1), where the electric current containers (16) are placed in a DC network (21).

Description

2 It is typical that such cranes are primarily driven by hydraulic drives with diesel engines. To ensure that such a crane can always operate reliably, even if a drive or engine were to fail, two engines and / or drives are provided per driven component. By providing this redundancy, it is possible to switch to the second engine should the first engine fail.10 The disadvantage of this redundancy is that such a crane comprises many more parts, making them more expensive and, moreover, larger and more complex in construction. 15 The document US2016 / 159619A1 describes a dual-drive energy-saving system for a rubber-tired gantry crane (RTG), consisting of a controller, a battery pack, a generator set, etc. The system changed the power supply of 20 traditional RTGs, which were powered by a single generator set or by a combination of a generator and a battery pack.Both the battery pack and the system's generator set can support the RTG operations independently of each other, thus forming a dual energy-saving system to improve the reliability of the equipment. The battery pack serves as the primary energy source for RTG and the output power can be closely matched to the required power, thereby reducing reactive loss and increasing energy efficiency. When the amount of electricity in the battery pack is high, the generator is switched off and power is supplied by the battery pack. When the amount of electricity in the battery pack is low, the generator is started to supply power directly to RTG. The excess energy can be used to charge the battery pack.The document PT2534085E relates to a crane, in particular a mobile harbour crane, with a diesel-electric drive, of which the AC generator feeds an AC circuit, with electric motors connected to the AC circuit that drive at least one slewing device, one hoisting device and one rocking device of the crane, as well as with at least one braking resistor connected to the AC circuit. In order to realize a crane, in particular a mobile harbour crane, with an improved hybrid drive system, it is proposed to connect short-term energy storage to the AC circuit for the temporary storage of at least the energy fed back into the AC circuit by the hoist. The document EP1753637B1 relates to an energy management system for a transport facility, in particular for a fuel- and electricity-powered motor vehicle, comprising an energy source, an intermediate energy storage and an electrical energy consumer, in particular an electric drive.The control and / or regulation of the energy supply, which depends on information regarding the future energy demand supplied by BE2024 / 5850 4 by means of at least one component of the means of transport, can be carried out by the energy management system by means of the intermediate storage and / or the energy demand. 5 None of the aforementioned documents offer a solution for the aforementioned disadvantage that the known edundancy comprises many more components, thereby making them more expensive and, moreover, also more voluminous and complex in construction. 10 The present invention aims to offer a solution for at least one of the aforementioned disadvantages.The present invention has as its object a modular electric drive for a ring crane, characterized in that the electric drive comprises one or more electric current containers, where each electric current container has an input for AC current for connecting an AC source, one or more outputs for DC current for connecting to drive components of the ring crane, where the electric current containers are placed in a DC network. An advantage is that the electric current containers are modular, this means that the output power of the different electric current containers can be combined because they are placed in a DC network. This has the consequence that a dual power supply or power source does not need to be provided for every component to be driven, and that in the event of failure or malfunction of one of the BE2024 / 5850 5 electric power containers, the others can take over. As a result, one additional electric power container is sufficient to make the entire drive reliable.5 Another advantage is that the electric drive is very easily scalable. If one wishes to apply it to a ring crane with a larger or smaller power requirement, one can provide more or fewer electric power containers. 10 Yet another advantage is that each electric power container is connected separately to an AC source, and that therefore the AC source for each electric power container does not necessarily have to be the same AC source. 15 However, no synchronization will be required between the different power sources or power supplies. One can therefore provide multiple independent AC sources, so that the reliability of the electric drive is better compared to the situation when one is dependent on a single AC source. A combination of multiple independent AC sources also allows for more flexibility of the available infrastructure and improves the feasibility of the local power supply.Finally, such an electric drive will be more environmentally friendly than a drive with diesel engines or a hydraulic drive, because there are no combustion gases and potential contamination with hydraulic oil is limited. It will also require less maintenance compared to hydraulic drives with pumps and filters. The aforementioned AC power input is provided for input voltages between 380 Volts and 500 Volts, and for input frequencies of 50 Hz and 60 Hz. The aforementioned DC power output is provided for voltages of 750 Volts, where the power is 680 kilowatts. In a practical design, the electric power container is equipped with an integrated braking resistor. When the electric power container is connected to the electricity grid, it will be possible to recover energy and return it to the electricity grid when lowering crane loads.20 When the electric current container is connected to a generator or the electricity grid that does not allow electricity consumption, the integrated thermal resistor will dissipate the energy when the ring crane lowers loads. 25 Preferably, the electric current container comprises a sea container or cargo container with two compartments, in which the aforementioned inlet for AC current and one or more outlets for DC current are provided in one of the compartments. 30 BE2024 / 5850 7 By using a sea container or cargo container, the transport of the ring crane to the construction site is facilitated. Moreover, the fact that it is a sea container or cargo container will also help with the modularity of the drive. The invention also relates to a ring crane equipped with an electric drive in accordance with the invention. It should be clear that the advantages of a ring valve according to the invention are similar to the advantages of an electric drive according to the invention.15 With the aim of better demonstrating the characteristics of the invention, some preferred forms of implementation of a modular electric drive for 20 ring cranes according to the invention are described below as examples without any restrictive character, with reference to the accompanying drawings, in which: Figure 1 schematically and in perspective depicts a ring crane according to the invention; 25 Figure 2 depicts the machine deck of Figure 1; Figure 3 is a schematic representation of the machine deck of Figure 2; Figure 4 schematically depicts an electric power container; 30 BE2024 / 5850 8 Figure 5 schematically depicts a variant of Figure 3; Figures 6 to 8 schematically depict a number of practical implementations of the electric drive according to the invention.5 The ring crane 1, schematically shown in Figure 1, is, as is known, constructed from a main boom 2 or mast, with an auxiliary boom 3 attached to it as an optional, but not necessary, extension, where mast 10 is mounted on a machine deck 4 with ballast weight 5 and wheel sets 6, with which the movable tracking 7 is provided. Both the main boom 2 and the auxiliary boom 3 are equipped with their own hook block 8a, 8b to which loads can be attached. The main boom 2 is equipped with a superlift mast 9 or aft mast; the auxiliary boom 3 is equipped with a lanyard 10 or 20 auxiliary boom mast. The main boom 7 is equipped with a hoisting system 11 and the auxiliary boom 3 with lower guy cables 12a and upper guy cables 12b. 25 A tensioning connection 13 is also provided between the superlift mast 9 and the ballast weight 5. The ballast weight5 is provided as freight containers or 30 sea containers filled with, for example, sand or soil. BE2024 / 5850 9 The machine deck4 is, as mentioned above, equipped with wheel sets6 with which the machine deck4, with rotating crane1, can turn or rotate over the curved tracks7.5 In this case the tracks7 form a circle, but this could also be a circular arc. Load distribution baffles14 are provided under the tracks7. The machine deck4 contains an electric drive1510 according to the invention, which is shown in detail in figure 2, where figure 3 schematically depicts the electric drive15, so that the principle is clear. As shown in figures 2 and 3, the electric drive15 according to the invention comprises a number of electric current containers16, which in this case, and preferably but not necessarily, are mounted on the machine deck4. 20 In this way the electric current containers16 are close to the components to be driven and can be kept as compact as possible. There are preferably at least two electric25 steam containers16, and in this case there are three electric current containers16, so that in the event of a failure of one of the two electric current containers16, the other current container16 can fully take over the drive of the rotating crane1 itself.30 BE2024 / 5850 10 Each electric power container16 has an input17 for AC power for connecting an AC source18. It is important to note that each electric power container16 has its own input17,5 independent of the input17 of another electric power container16. In addition, each electric power container16 also has one or more outputs19 for DC power for connecting10 a component to be driven20 of the ring crane1. These components include, among others, winches20 and wheel sets6. 15 To form the electric drive15, the electric power containers16 are placed in a DC grid21, DC network or DC circuit by connecting them to each other in the appropriate manner. 20 In Figure 3, this DC grid21 is schematically shown. The DC grid21 is created on the machine deck4 of the ring crane1. In addition, the electric power containers are connected in a circuit, which provide a basic power supply for monitoring and standby.In addition to the three electric power containers16, the electric drive15 from the example in figures 230 and 3, though not necessary for the invention, is also BE2024 / 5850 11 equipped with a so-called basic power electric power container23. Such basic power electric power container23 serves to provide a basic power supply for the control and standby of the electric power containers16, the components to be driven20, 20a, 6, driver's cab24; and to supply power to, among other things, a computer installation and / or an air conditioning installation and / or lighting / or other supporting or auxiliary components of each crane1. In addition, the basic power electric power container23 also serves to provide a standby power supply when each crane1 is switched off and for15 providing an emergency power supply in the event of power loss from the AC sources18 in the aforementioned DC network 21.The basic power electric current container23 is similar to the other three electric current containers16 and has an input25 for AC current for connecting an AC source18, one or more outputs26 for connecting one of the aforementioned supporting or auxiliary components, whereby the basic power electric current container23 is placed in the AC circuit22 and is further equipped with a battery. The input25 of the basic power electric current container23 can be connected to a standard electricity grid18, for example via a standard socket. Figure 3 schematically shows how the basic power electric current container23 is connected to the DC grid5 21 and is connected to the relevant supporting or auxiliary components, in this case to the driver's cab24, via its output26.Via the AC circuit 22, the basic power supply of the electric power container 23 is connected to the electric power containers 16, the components to be driven 20, being the bearings 20 on the wheel sets 6, the driver's cab 24, the computer installation and / or an air conditioning installation of the crane 1. Note that 15 in Figure 3, for clarity, not all connections of the AC circuit 22 are included. Ring crane 1 will measure sensors comprising certain parameters regarding the operation of ring crane 1. Via the AC circuit 22 with the basic power supply for control and standby, power is supplied to transmit all these measured parameters via a data network to, for example, the computer system in the driver's cab 24, for the control of ring crane 1. 25 The electrical current containers 16 are, in this case, though not necessary for the invention, equipped with an integrated braking resistor 27, an AC / DC converter 28 and 30 BE2024 / 5850 13 of an isolation transformer 29; these are shown in figure 4.When the electric power container16 is not connected to the electricity grid and / or to a battery to recover current, the current generated by means of the ears20 when a load is lowered will be dissipated in this brake resistor27, after which the generated heat is cooled. 10 A practical design of an electric power container16 is shown in figure 4. An electric power container16 comprises a shipping container 30 or cargo container30 with standard dimensions in which 15 two chambers are provided: a first chamber31 and a second chamber32. In the second chamber32, the aforementioned input17 is for AC current, an AC-to-DC converter28, and one or more outputs19 are for DC current and in this case also provide the isolation transformer29. In the first chamber31 the integrated resistor27 is provided, which can be water-cooled, as well as the isolation transformer29, if it is not located in the second chamber32. Figure 5 shows an alternative design of the electric drive15 from figure 3 in a more general view.BE2024 / 5850 14 The electric current containers16 are connected to each other in a DC grid21 or DC network or DC group, together forming a basic power electric current container23. 5 Each electric current container16 with its outputs 19 connected to one or more of the wheels20a or wheel sets6 of the driving crane1. In this case, not every electric current container16 needs to be connected to 10 the same number or similar components to be driven20. Each input17 for AC current is configured to be connected to an AC source18, which can be a 15 electricity grid18, a generator18b, such as a diesel generator or a battery (buffer)18c coupled to an electricity grid. It is important to note that each electric current container16 can be connected to its own individual AC source18, or that all, or a number of, the electric current containers16 share or have one AC source18 in common. In Figure 5, each electric current container16 has its own AC source18.Figure 6 gives the example where all three electric power containers16 are connected to the electricity grid18 with their input17. The AC source18 is, in other words, the electricity grid18a, but this could also be a diesel generator18 or three diesel generators18b. Figure 7 shows the example where two electric power containers16 are connected to a battery buffer 18c, which is also connected to an electricity grid 18a. This allows energy to be recovered via the winches20 when a crane1 lowers a load which can be stored in the battery buffer18c.10 Finally, Figure 8 shows a mixed arrangement, where two electric power containers16 are connected to the electricity grid18a and one electric power container16 is connected to a diesel generator15 18b. It should be clear that different arrangements are possible without going beyond the scope of the invention.The general operation of ring crane 1 to lift loads, rotate ring crane 1 to move the loads, and subsequently lower them to another location, is, as is known, for existing ring cranes 1. To drive and activate the various components 20, such as winches 20a and 25 the wheel sets 6, use is made of the electric drive 15 whereby the electric current containers 16 supply power to the various components 20 via the DC network 21. 30 BE2024 / 5850 16 Additionally, during operation via the AC circuit 22, parameters of the sensors of ring crane 1 will be sent to a control unit of ring crane 1 located, for example, in the driver's cab 24. 5 The basic power electric current container 23 will specifically provide power for the driver's cab 24, the computer installations and the air conditioning installation of ring crane 1, and possibly also for the lighting of ring crane 1.10 When, for example, crane 1 is switched off at night, the basic power supply of electric power container 23 will continue to provide a standby power supply via the AC circuit 22 to, for example, the 15 driver's cab 24, a computer installation and / or an air conditioning installation of crane 1. By working with a DC network 21 constructed from the electric power containers 16, 23, various 20 components 20, 20a, 6, 24 can be driven with a limited number of electric power containers 16. The power supplied by the electric power containers 16 is, as it were, combined in the DC network 21. 25 Depending on the required power, the appropriate number of power containers 16 is selected, supplemented with one extra.During operation, the various components20,30 20a,6,24 are driven, and should a failure occur BE2024 / 5850 17 in one of the electric current containers16 such that it can no longer supply DC power, for example due to a defect in the electric current container16 itself or in the relevant AC source18, the other electric current containers16 in the DC network21 can take over.5 The loss of power due to the failure of one of the electric current containers16 can be compensated by, for example, temporarily driving the rotating crane1 at a slower speed or by better coordinating the combination of lifting loads10 and rotating the rotating crane1 on the tracks7. In comparison with the redundancy of motors and / or drives of the cranes to guarantee reliable operation, an electric drive according to the invention is at least as reliable by providing only one additional electric current container.20 In addition, extra reliability, better feasibility and flexibility of the available infrastructure are also guaranteed by providing various AC sources 18 for the electric power container16, so that one is not dependent on a single AC source18. 25 When, in the very exceptional situation, none of the electric power containers16 receive AC power via the input18, the basic power electric power container 23 acts as an emergency power supply. 30 BE2024 / 5850 18 Via its battery, it will be able to supply power via the AC grid22 for some time, for example a few minutes, to the electric power containers16 and / or to the components to be driven20 of the ring crane1. This will allow the ring crane1 to be shut off in a safe manner5 in similar emergency situations. The present invention is by no means limited to the example described and ende.