Method and rack storage system with increased safety when stopping a stacker crane

Description

[0001] The invention relates to a method for operating a storage and retrieval machine, in which the storage and retrieval machine has an inverter and a drive motor for the storage and retrieval machine that can be connected thereto, and in which the inverter is at least temporarily electrically connected to an energy storage device that is connected to an electrical supply network via a supply circuit. Furthermore, the invention relates to a storage and retrieval system comprising a storage and retrieval machine that has an inverter and a drive motor for the storage and retrieval machine that can be connected thereto, an energy storage device that is at least temporarily electrically connected to the inverter, and a supply circuit that is connected to an electrical supply network and to the energy storage device.

[0002] Such a method and such a rack storage system are known in principle. For example, EP 2 372 892 A1 discloses a device and method for temporarily storing electrical braking energy from a motor powered by an inverter. If a maximum voltage is reached at the energy storage capacitor, the braking resistor is switched on, enabling emergency operation and the motor to be braked despite the energy storage capacitor being full. As soon as the energy storage capacitor is at least partially discharged, the energy storage device resumes its storage function.

[0003] The arrangement disclosed in EP 2 372 892 A1 thus serves to protect the energy storage capacitor and assumes that at least a portion of the recuperative energy can be fed back into the energy storage capacitor and that only any excess energy is thermally converted. The braking resistor can therefore be dimensioned small. However, EP 2 372 892 A1 does not address a fault scenario in which the electrical energy generated during deceleration cannot be fed back into the energy storage device at all, for example, due to a fault in the electrical grid.

[0004] EP 3 543 200 A1 also discloses a storage and retrieval machine and a method for controlling the same, in which electrical energy is temporarily stored in an energy storage device. At least one electrical operating parameter of the storage and retrieval machine is monitored, and the feed of electrical energy into the energy storage device and / or the withdrawal of electrical energy from the energy storage device is controlled depending on this electrical operating parameter.

[0005] WO 2016 / 094923 A2 also discloses a warehouse arrangement with multiple storage locations for piece goods, with multiple automated storage and retrieval machines for storing and retrieving the piece goods, and with at least one power supply for said storage and retrieval machines. The warehouse arrangement also includes at least one power storage unit for the power supply.

[0006] One object of the invention is to provide an improved method and an improved rack storage system. In particular, a possibility is to be created for electrically braking a storage and retrieval machine even when the electrical energy generated during deceleration cannot be fed back into the energy storage device.

[0007] The invention is defined by the method claims 1 and 5 and by the corresponding device claims 7 and 11.

[0008] The proposed measures ensure that a storage and retrieval machine can be electrically braked even if the electrical energy generated during deceleration cannot be fed back into the energy storage device, for example because of a fault in the electrical network or because the storage and retrieval machine is disconnected from the electrical network or the energy storage device. A mechanical brake, in particular a self-locking mechanical brake, can therefore be omitted. A particular advantage is that a storage and retrieval machine can be easily moved by hand without any further measures once the storage and retrieval machine has stopped, since the electronic brake has no or only a negligible effect when stationary or traveling slowly.

[0009] In the present method, a procedure is adopted that is diametrically opposed to EP 2 372 892 A1, because there a braking resistor is switched on when the maximum voltage at the energy storage capacitor is reached, whereas in the present method the braking energy is conducted into a braking resistor when the supply voltage for the inverter is below the first supply voltage threshold or below a lower second supply voltage threshold and / or when the inverter is electrically separated from the energy storage device.

[0010] The energy storage unit can be designed, in particular, as a stationary energy storage unit. Specifically, the energy storage unit can be electrically connected to the inverters of multiple storage and retrieval machines. The storage system is thus structured hierarchically.

[0011] The storage and retrieval machine is designed for storing and / or retrieving piece goods from a storage rack of a rack storage system. The storage and retrieval machine preferably comprises a load-handling device for storing and retrieving piece goods from storage locations in the rack storage system. The load-handling device can be arranged on or at a loading platform, wherein the loading platform forms a receiving surface for at least one piece of goods. In this case, it can be provided that the storage and retrieval machine is designed as a multi-level storage and retrieval machine. The multi-level storage and retrieval machine has a mast on which the loading platform is movable. Alternatively, it can be provided that the storage and retrieval machine is designed as a single-level storage and retrieval machine, for example as a shuttle.

[0012] Advantageous embodiments and further developments of the invention will now become apparent from the dependent claims and from the description in conjunction with the figures.

[0013] It is advantageous if a controllable drive motor switching element connects the drive motor to the inverter when the supply voltage for the inverter is above the first supply voltage threshold and / or when the inverter is electrically connected to the energy storage device, and connects the drive motor to the braking resistor when the supply voltage for the inverter is below the first supply voltage threshold or below the lower second supply voltage threshold and / or when the inverter is electrically disconnected from the energy storage device.

[0014] The drive motor switching element can be designed as an electronic switching element, for example as a transistor, or as an electromechanical switching element, for example as a relay.

[0015] A first control for the controllable drive motor switching element can be designed to detect a supply voltage for the inverter and / or the status of an electrical connection between the inverter and the energy storage device and to control the controllable drive motor switching element in such a way that that the controllable drive motor switching element connects the drive motor to the inverter when the first controller for the controllable drive motor switching element detects a supply voltage for the inverter above a first supply voltage threshold and / or detects that the inverter is electrically connected to the energy storage device, and that the controllable drive motor switching element connects the drive motor to the braking resistor when the first controller for the controllable drive motor switching element detects a supply voltage for the inverter below the first supply voltage threshold or below a lower second supply voltage threshold and / or detects that the inverter is electrically disconnected from the energy storage device.

[0016] The first control for the controllable drive motor switching element is connected to a control input of the drive motor switching element, for example to a gate terminal or base terminal of a transistor or to a control coil of a relay.

[0017] It is also advantageous if the drive motor switching element in the presented method comprises a drive motor relay or is designed as such and a switching contact of the drive motor relay connects the drive motor to the inverter when a control coil of the drive motor relay acting on the switching contact, which is arranged in a current path between the switching contact and the energy storage device, is supplied with a voltage that is higher than a switch-on voltage of the drive motor relay and the drive motor relay is energized, and connects the inverter to the braking resistor when the voltage at the control coil is below a switch-off voltage of the drive motor relay and the drive motor relay has dropped out.

[0018] In the same way, it is advantageous if the drive motor switching element in the presented shelf storage system comprises a drive motor relay or is designed as such and the drive motor can be connected to the inverter or the braking resistor via a switching contact of the drive motor relay and a control coil of the drive motor relay acting on the switching contact is arranged in a current path lying between the switching contact and the energy storage device.

[0019] In this embodiment, a separate first control for the drive motor switching element is unnecessary, since the switching of the drive motor between the energy storage device and the braking resistor is handled directly by the control coil of the drive motor relay. This embodiment is therefore particularly simple in design and particularly reliable in operation.

[0020] It is also advantageous if a controllable energy storage switching element connects the inverter to the energy storage device when a grid voltage of the electrical supply network is above a first grid voltage threshold and / or when the energy storage device is electrically connected to the electrical supply network, and disconnects the inverter from the energy storage device when the grid voltage of the electrical supply network is below the first grid voltage threshold or below a lower second grid voltage threshold and / or when the energy storage device is electrically disconnected from the electrical supply network.

[0021] The energy storage switching element can also be designed as an electronic switching element, for example as a transistor, or as an electromechanical switching element, for example as a relay.

[0022] The energy storage switching element can be used to de-energize the stacker crane. This can be done actively by a user who, for example, wishes to maintain the stacker crane, or due to a condition of the power grid. If the power grid fails, for example, people who are not familiar with the electrical structure of the shelving system could mistakenly assume that the stacker crane is de-energized when the power grid fails. However, this is not necessarily the case due to the energy storage device, which can be charged with a life-threatening voltage even in the event of a power grid failure. The stacker crane could also actively and possibly uncontrollably move using the energy from the energy storage device.For safety reasons, the energy storage device is therefore switched off from the storage and retrieval machine in the event of a power failure, so that access to a rack aisle, for example, is safe.

[0023] A second control for the controllable energy storage switching element can be designed to detect a mains voltage of the electrical supply network and / or the status of an electrical connection between the energy storage device and the electrical supply network and to control the controllable energy storage switching element in such a way that that the controllable energy storage switching element connects the inverter to the energy storage device when the second controller for the controllable energy storage switching element detects a grid voltage of the electrical supply network above a first grid voltage threshold, and / or detects that the inverter is electrically connected to the supply network, and that the controllable energy storage switching element disconnects the inverter from the energy storage device when the second controller for the controllable energy storage switching element detects a grid voltage of the electrical supply network below the first grid voltage threshold or below a lower second grid voltage threshold, and / or detects that the inverter is electrically disconnected from the supply network.

[0024] The second control for the controllable energy storage switching element is connected to a control input of the energy storage switching element, for example to a gate terminal or base terminal of a transistor or to a control coil of a relay.

[0025] It is also advantageous if the energy storage switching element in the presented method comprises an energy storage relay or is designed as such and a switching contact of the energy storage relay connects the inverter to the energy storage device when a control coil of the energy storage relay acting on the switching contact, which is arranged in a current path between the energy storage device and the electrical supply network, is supplied with a voltage that is higher than a switching voltage of the energy storage relay and the energy storage relay is energized, and disconnects the inverter from the energy storage device when the voltage at the control coil is below the switching voltage of the energy storage relay and the energy storage relay has dropped out.

[0026] In the same way, it is advantageous if the energy storage switching element in the presented shelf storage system comprises an energy storage relay or is designed as such and the inverter can be connected to and separated from the energy storage device via a switching contact of the energy storage relay and a control coil of the second relay acting on the switching contact is arranged in a current path lying between the energy storage device and the electrical supply network.

[0027] In this embodiment, a separate second control for the energy storage switching element is unnecessary, since the connection of the energy storage device to the inverter and the disconnection of the energy storage device from the inverter are handled directly by the control coil of the energy storage relay. This embodiment is therefore also particularly simple in design and particularly reliable in operation.

[0028] Generally, disconnecting the energy storage device from the inverter also causes the drive motor to switch to the braking resistor, either by evaluating the switching state of the energy storage device's switching element in the storage and retrieval machine or by the voltage drop across the inverter associated with the disconnection. A switching cascade is formed in this way, which is particularly advantageous.

[0029] At this point it is also noted that the variants and advantages disclosed for the presented method apply equally to the presented shelf storage system and vice versa.

[0030] For a better understanding of the invention, it is explained in more detail using the following figures.

[0031] They show in a highly simplified, schematic representation: Fig. 1 shows an exemplary and schematic representation of a shelving system with several multi-level storage and retrieval machines and an associated power supply; Fig. 2 shows a front view of a shelving system with several single-level storage and retrieval machines supplied by a power supply; Fig. 3 shows a front view of a shelving system with several single-level storage and retrieval machines supplied by several power supplies; Fig. 4 shows an electrical schematic diagram of a shelving system with a controlled drive motor switching element; Fig. 5 shows an electrical schematic diagram of a shelving system with a drive motor switching element designed as a relay and whose control coil is connected to the inverter input; Fig. 6 shows Fig. 4 , but with a controlled energy storage switching element; Fig. 7 as Fig. 5, but with an energy storage switching element designed as a relay and whose control coil is connected to the rectifier input; and Fig. 8 as Fig. 7 , but with a drive motor switching element whose control coil is connected to the inverter output.

[0032] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure and, in the event of a change in position, is to be applied analogously to the new position.

[0033] Fig. 1shows a rack storage system 1a with several storage locations 2, which are arranged next to each other and one above the other, as well as with several computer-controlled storage and retrieval machines 3, which are movable relative to the storage locations 2 (Note: in the Fig. 1 the rear storage and retrieval machine 3 is only partially visible). The rack storage system 1a further comprises a power supply 4 for the aforementioned storage and retrieval machines 3 and an energy storage device C, which is integrated into the power supply 4 in the example shown.

[0034] In this example, the storage locations 2 are organized in rack rows 5, which are arranged adjacent to rack aisles 6 and can accommodate a single piece of goods (single-deep storage) or multiple pieces of goods (multi-deep storage) in the depth direction. The storage and retrieval machines 3 are designed as multi-level storage and retrieval machines and each comprise a chassis 7, which is movable on rails 8, and a mast 9, which is connected to the chassis 7. In the Fig.1 the storage and retrieval machine 3 travels on two rails 8, but of course a storage and retrieval machine 3 can also travel on only one rail 8, which can in particular be designed as an I-profile.

[0035] Furthermore, the multi-level storage and retrieval machine 3 comprises a loading platform 10 that can be moved (raised and lowered) on the mast 9. A load-handling device 11 for storing the piece goods in the storage locations 2 and retrieving the piece goods from the storage locations 2 is arranged on the loading platform 10. The loading platform 10 forms a receiving surface for at least one piece of goods. Such a multi-level storage and retrieval machine 3 is disclosed, for example, in EP 2 419 365 B1 and is the subject of this disclosure. With the aid of the multi-level storage and retrieval machines 3, piece goods can be stored in a storage location 2 or retrieved from it in a manner known per se. The piece goods in question are transported with the aid of the loading platform 10 from a feed conveyor system (not shown) to the storage location 2 or from the storage location 2 to a removal conveyor system (not shown). The feed conveyor system and / or removal conveyor system can be designed, for example, as roller conveyors.

[0036] The power supply 4 is electrically connected to the rails 8 and the multi-level storage and retrieval machines 3 via power lines 12, so that their electric drive motors can be supplied with electrical energy. A first drive motor (travel drive) is used to move the multi-level storage and retrieval machine 3 along the rack aisle 6, a second drive motor (lifting drive) is used to raise and lower the loading platform 10, and a third drive motor (storage and retrieval drive) is used to move the load-handling device 11 in and out. The load-handling device 11, in turn, can comprise at least a fourth drive motor, which is used to adjust a transport element for transporting piece goods between the storage location 2 and the loading platform 10. Of course, the power can also be transmitted in other ways, for example via trailing cables.In the example shown, the power supply 4 is assigned to two multi-level storage and retrieval machines 3. Of course, the power supply 4 could also supply more than two multi-level storage and retrieval machines 3, or one power supply 4 could be assigned to each multi-level storage and retrieval machine 3.

[0037] According to one possible embodiment, the load-handling device 11 comprises telescopic arms, which are arranged on or at the loading platform 10 and each comprise slides that can be extended / retracted perpendicular to the rack aisle 6. The outer slide of the telescopic arms comprises transport elements arranged at least at its opposite ends and adjustable relative to the loading platform 10, by means of which a piece of goods to be stored or retrieved can be gripped behind. Such a load-handling device 11 is known, for example, from DE 20 2004 004 620 U1 and US Pat. No. 6,923,612 B2 and is the subject of this disclosure.

[0038] In this embodiment, the energy storage device C is housed directly in the power supply 4 in a common control cabinet. Of course, the energy storage device C could also be housed in a separate housing. Furthermore, it should be noted that other electrical / electronic devices for operating the multi-level storage and retrieval machines 3, such as circuit breakers, contactors, controllers, measuring devices, and the like, can also be housed in the control cabinet of the power supply 4. Electrical / electronic devices for operating the multi-level storage and retrieval machines 3, in particular a controller for the same, can also be housed in the multi-level storage and retrieval machine 3.

[0039] The energy storage device C generally serves to store the energy generated during the deceleration of a multi-level storage and retrieval machine 3 and to release it again when needed, i.e., when accelerating this or another multi-level storage and retrieval machine 3. In this way, current peaks in the supply line to the power supply 4 are avoided, and the energy consumption of the storage system 1a is reduced. This applies not only to the deceleration and acceleration of, for example, the chassis 7, but also to all moving parts of the multi-level storage and retrieval machine 3, in particular, the raising and lowering movement of the loading platform 10.

[0040] As in the Fig. 1As shown, the energy storage device C is not connected to the storage and retrieval machine 3, but to a (stationary) power supply 4 for the storage and retrieval machines 3, in order to feed the energy generated by the drive motors of the storage and retrieval machines 3 into the energy storage device C via the (bidirectional) power supply.

[0041] In the above example, it was assumed that the storage and retrieval machines 3 are designed as multi-level storage and retrieval machines and that the power supply 4 and the energy storage device C are assigned to the storage and retrieval machines 3 of several rack aisles 6. However, this is by no means the only conceivable possibility. The rack storage system 1a can also have just one rack aisle 6. It is also possible for at least one multi-level storage and retrieval machine to be arranged in the single rack aisle 6 or in the several rack aisles 6 on levels one above the other. This results in storage areas in which the storage locations 2 are located, each of which is assigned a multi-level storage and retrieval machine. In this embodiment, the power supply 4 and the energy storage device C are assigned to several multi-level storage and retrieval machines 3 of one rack aisle 6.If only one rack aisle 6 and one multi-level stacker crane 3 are provided in this rack aisle 6, the power supply 4 and the energy storage device C are only assigned to this multi-level stacker crane 3.

[0042] It is also conceivable for the storage and retrieval machines to be designed as single-level storage and retrieval machines. In particular, the power supply 4 and the energy storage device C can be assigned to single-level storage and retrieval machines at multiple levels of a rack aisle 6, with the storage locations 2 in turn being organized into rack rows 5, which are arranged adjacent to at least one rack aisle 6.

[0043] Fig. 2shows an example of a rack storage system 1b with a row of shelves 5 with several storage locations 2 arranged on four levels. A single-level storage and retrieval machine 3' is provided on each level, which can transport piece goods 13 to and from the storage locations 2 on a level. The storage and retrieval machines are designed as single-level storage and retrieval machines 3' and each comprise a chassis 14 that can be moved on rails 8, and a loading platform 10. A load-handling device 11 for storing the piece goods 13 in the storage locations 2 and retrieving the piece goods 13 from the storage locations 2 is arranged on or at the loading platform 10. The loading platform 10 forms a receiving surface for at least one piece of goods 13. Such a single-level storage and retrieval machine 3' and such a load-handling device 11 are disclosed, for example, in WO 2013 / 090970 A2 or EP 2 351 698 B1 and are the subject of this disclosure.

[0044] The load-handling device 11 comprises telescopic arms, which are arranged on or at the loading platform 10 and each comprise slides that can be extended / retracted perpendicular to the rack aisle 6. The outer slide of the telescopic arms comprises transport elements arranged at its opposite ends and between them, which are adjustable relative to the loading platform 10 and can be used to grip behind a piece of goods 15 to be stored or retrieved.

[0045] Even though the illustrated embodiment includes a single-level storage and retrieval machine 3' on each level, it is equally possible for only some of the levels to include a single-level storage and retrieval machine 3'. In this case, a lifting device for single-level storage and retrieval machines 3' is provided, which can pick up a single-level storage and retrieval machine 3' from one level and transfer it to another. Such a lifting device is described, for example, in WO 2012 / 106744 A1.

[0046] In addition, a lift 15 is located in front of the rack row 5, which lift has a mast 16 and a loading platform 17 that can be moved along it. During the storage process, a piece of goods 13 to be stored is transferred from the loading platform 17 to a staging device 18. This piece of goods 13 remains on the staging device 18 until the single-level storage and retrieval machine 3' picks up the piece of goods 13. The single-level storage and retrieval machine 3' receives the piece of goods 13 and transports it to its storage location 2. During retrieval, the reverse process occurs. The combination of the single-level storage and retrieval machines 3' and the lift 15 essentially fulfills the same function as a multi-level storage and retrieval machine 3a, 3a'. The lift 15 can, in particular, also be provided in the form of a paternoster.

[0047] The power supply 4 is electrically connected to the rails 8 and to the single-level storage and retrieval machines 3' on each level via power lines 12, so that their electric drive motors can be supplied with electrical energy. A first drive motor (travel drive) is used to move a single-level storage and retrieval machine 3' along the rack aisle 6, and a second drive motor (storage and retrieval drive) is used to move the load-handling device 11 in and out. The load-handling device 11, in turn, can comprise at least one third drive motor, which is used to adjust a transport element for transporting piece goods 13 between the storage location 2 and the loading platform 10.

[0048] Of course, power transmission can also be achieved in other ways, for example via a conductor line, as described, for example, in WO 2013 / 090970 A2. In the example shown, the power supply 4 is assigned to all single-level storage and retrieval machines 3'.

[0049] The Fig. 1 What has been said now also applies to the embodiment according to Fig. 2 , wherein the power supply 4 and the energy storage C are assigned to storage and retrieval machines 3' of several levels of a rack aisle 6. In addition, the power supply 4 and the energy storage C can also be assigned to the lift 15 and utilize its generator-generated energy.

[0050] Fig. 3now shows an embodiment in which a first power supply 4 is assigned to a first travel level, a second power supply 4' to a second travel level, and a third power supply 4" to a third and fourth travel level. The single-level storage and retrieval machines 3' are thus partially supplied with electrical energy by different power supplies 4..4". The power supplies 4..4" each have an energy storage device C. The electrical energy generated by a generator when braking a single-level storage and retrieval machine 3' is stored in the energy storage device C of the assigned power supply 4..4" and used at a later time to accelerate this or another single-level storage and retrieval machine 3'.

[0051] This design proves particularly advantageous for large rack storage systems 1c, since in the event of a fault on a power supply 4..4" and / or an energy storage device C, only the single-level stacker crane 3' or the group of single-level stacker cranes 3' assigned to the respective power supply 4..4" and / or the respective energy storage device C needs to be shut down. The other single-level stacker cranes 3' or the other group(s) of single-level stacker cranes 3' can continue to operate normally. This achieves a high level of system availability of the rack storage system 1c.

[0052] The Fig. 1 The above also applies to the embodiment according to Fig. 3 . In addition, a power supply 4..4" and an energy storage C can also be assigned to the lift 17 and utilize its generator-generated energy.

[0053] The Fig. 4 to 8now show electrical circuit diagrams of possible embodiments for supplying storage and retrieval machines 3a..3e with electrical energy using power supplies 4a..4e.

[0054] Specifically, the embodiment according to Fig. 4a power supply 4a and a storage and retrieval machine 3a electrically connected thereto. The storage and retrieval machine 3a has a drive motor M, an inverter W, a braking resistor R, a drive motor switching element S1, a first controller CTR1 and a device for measuring a first supply voltage V1 for the inverter W. The power supply 4a has a supply circuit G, which in the present example is designed as a rectifier, and an energy storage device C electrically connected thereto. The rectifier G also has three connections to an electrical supply network L1..L3. With the drive motor switching element S1, the drive motor M can be connected either to the braking resistor R or to the inverter W.A connecting piece located between the power supply 4a and the storage and retrieval machine 3a for providing an electrical connection between the power supply 4a and the storage and retrieval machine 3a can, for example, comprise the rails 8 and / or the cabling 12.

[0055] When accelerating and to maintain movement, the storage and retrieval machine 3a draws electrical energy from the electrical supply network L1..L3 via the inverter W and the rectifier G. A three-phase alternating voltage present in the electrical supply network L1..L3 is converted into a direct voltage by means of the rectifier G, which is smoothed by the energy storage device C and fed to the inverter W. The inverter W converts the direct voltage back into an alternating voltage, which drives the drive motor M. The drive motor switching element S1 is in a position in which the drive motor M is connected to the inverter W.

[0056] When decelerating the storage and retrieval machine 3a, two cases must be distinguished: Electrical energy generated when decelerating the storage and retrieval machine 3a is fed back into the energy storage device C when a supply voltage V 1 for the inverter W is above a first supply voltage threshold, and is fed into the braking resistor R when the supply voltage V 1 for the inverter W is below the first supply voltage threshold or below a lower second supply voltage threshold.

[0057] For this purpose, the supply voltage V 1 at the input of the inverter W is measured in this embodiment and evaluated by the first controller CTR1. The first controller CTR1 controls the drive motor switching element S1 so that it connects the drive motor M to the inverter W when the supply voltage V 1 for the inverter W is above the first supply voltage threshold, and connects the drive motor M to the braking resistor R when the supply voltage V 1 for the inverter W is below the first supply voltage threshold or below the lower second supply voltage threshold.

[0058] The drive motor switching element S1 can be designed as an electronic switching element, for example, as a transistor, or as an electromechanical switching element, for example, as a relay. The first controller CTR1 can be connected to a control input of the drive motor switching element S1 for controlling the drive motor switching element S1, for example, to a gate terminal or base terminal of a transistor or to a control coil of a relay.

[0059] The first supply voltage threshold and, if applicable, the second supply voltage threshold are selected such that the inverter W and its controller, as well as the first controller CTR1, are sufficiently supplied with electrical energy and remain functional at least until the drive motor M switches to the braking resistor R. At the latest when the sufficient supply to the inverter W and its controller, as well as the first controller CTR1, is no longer available, the drive motor M is switched to the braking resistor R. The switching state of the drive motor switching element S1 should be maintained even if the voltage continues to drop.These measures ensure that the storage and retrieval machine 3a can be electrically braked even if the electrical energy generated during deceleration cannot be fed back into the energy storage device C, for example because there is a fault in the electrical network and the inverter W and its control system are no longer sufficiently supplied and therefore fail.

[0060] A mechanical brake, especially a self-locking mechanical brake, can be omitted. This is particularly advantageous because the storage and retrieval machine 3a can be easily moved by hand after stopping without any further action, since the brake, via the braking resistor R, has no or only a negligible effect when stationary or traveling slowly.

[0061] In order to simplify the control of the drive motor switching element S1 and to increase the operational reliability of the shelf storage system 1a..1c, an arrangement according to Fig. 5The power supply 4b of the Fig. 5 is similar to the power supply 4a of the Fig. 4 , and the storage and retrieval machine 3b of the Fig. 5 is the storage and retrieval machine 3a of the Fig. 4 similar. In this embodiment, the drive motor switching element S1 of the storage and retrieval machine 3b comprises a drive motor relay or is designed as such and accordingly has a switching contact and a control coil acting on the switching contact. The control coil is arranged in a current path lying between the switching contact of the relay and the energy storage device C, in particular in a current path lying between the inverter W and the energy storage device C, as in the Fig. 5 is the case.

[0062] In this embodiment, the switching contact of the drive motor relay the drive motor M with the inverter W when the control coil of the drive motor relay is supplied with a voltage that is higher than a switch-on voltage of the drive motor relay and the drive motor relay is energized, and the drive motor M with the braking resistor R when the voltage at the control coil is lower than a switch-off voltage of the drive motor relay and the drive motor relay has dropped out.

[0063] In this embodiment, a separate control CTR1 for the drive motor switching element S1 is therefore unnecessary, since the switching of the drive motor M between the energy storage device C and the braking resistor R is handled directly by the control coil of the drive motor relay. This embodiment is therefore particularly simple in design and particularly reliable.

[0064] Fig. 6 shows a further embodiment with a storage and retrieval machine 3c and a power supply 4c, which corresponds to the Fig. 4is very similar to the embodiment shown. In contrast, a controllable energy storage switching element S2 is provided between the energy storage device C and the inverter W. In addition, the power supply 4c comprises a second controller CTR2 and a device for measuring the mains voltage V 2 of the electrical supply network L1..L3.

[0065] The second controller CTR2 for the controllable energy storage switching element S2 can be designed to detect the mains voltage V 2 of the electrical supply network L1..L3 and / or the status of an electrical connection between the energy storage device C and the electrical supply network L1..L3. The second controller CTR2 controls the energy storage switching element S2 such that it connects the inverter W to the energy storage device C when a grid voltage V 2 of the electrical supply network L1..L3 is above a first grid voltage threshold and / or when the energy storage device C is electrically connected to the electrical supply network L1..L3, and disconnects the inverter W from the energy storage device C when the grid voltage V 2 of the electrical supply network L1..L3 is below the first grid voltage threshold or below a lower second grid voltage threshold and / or when the energy storage device C is electrically disconnected from the electrical supply network L1..L3.

[0066] The energy storage switching element S2 can in turn be designed as an electronic switching element, for example, a transistor, or as an electromechanical switching element, for example, a relay. The second controller CTR2 is connected to a control input of the energy storage switching element S2, for example, to a gate terminal or base terminal of a transistor or to a control coil of a relay.

[0067] With the help of the energy storage switching element S2, the storage and retrieval machine 3c and the rails 8 can be de-energized. This can be done actively by a user who, for example, wishes to enter rack aisle 6 or to service the storage and retrieval machine 3c, or simply due to the condition of the supply network L1..L3. If this fails, persons who do not have precise knowledge of the electrical structure of the shelf storage system 1a..1c could make the erroneous assumption that the storage and retrieval machine 3c and the rails 8 are de-energized if the supply network L1..L3 fails. However, this is not necessarily the case due to the energy storage device C, which can be charged with a life-threatening voltage even if the supply network L1..L3 fails. The storage and retrieval machine 3c could also move actively and possibly uncontrollably using the energy from the energy storage device C.For safety reasons, the energy storage device C is therefore switched off from the storage and retrieval machine 3c and the rails 8 in the event of a failure of the supply network L1..L3, so that access to the rack aisle 6 is safe.

[0068] The status of the supply network L1..L3 can be determined by measuring the second mains voltage V2 or by receiving a message from another unit that monitors the status of the supply network L1..L3. For example, a central monitoring unit at the network access point of the rack storage system 1a..1c could send a corresponding message if it detects a malfunction in the supply network L1..L3.

[0069] In order to simplify the control of the energy storage switching element S2 and to increase the operational reliability of the shelf storage system 1a..1c, an arrangement according to Fig. 7 be provided with a storage and retrieval machine 3d, which corresponds to the storage and retrieval machine 3b from Fig. 5and a power supply 4d, which is the same as that of the Fig. 6 is very similar. In this embodiment, the energy storage switching element S2 comprises an energy storage relay or is designed as such and accordingly has a switching contact and a control coil acting on the switching contact. The control coil is arranged in a current path lying between the energy storage device C and the electrical supply network L1..L3.

[0070] In this embodiment, the switching contact of the energy storage relay the inverter W with the energy storage device C, when a control coil of the energy storage relay acting on the switching contact, which is arranged in a current path between the energy storage device C and the electrical supply network L1..L3, is supplied with a voltage which is higher than a switching voltage of the energy storage relay and the energy storage relay is energized, and disconnects the inverter W from the energy storage device C when the voltage at the control coil is below the switching voltage of the energy storage relay and the energy storage relay has dropped out.

[0071] In this embodiment, a separate control for the energy storage switching element S2 is omitted, since the connection of the energy storage device C to the inverter W and the disconnection of the energy storage device C from the inverter W are handled directly by the control coil of the energy storage relay. This embodiment is therefore also particularly simple in design and particularly reliable in operation.

[0072] Fig. 8 finally shows one of the Fig. 7 similar embodiment. In contrast, the control coil of the drive motor switching element S1 is connected in the part of the circuit located between the inverter W and the braking resistor R. The control coil is therefore supplied with an alternating voltage and not as in Fig. 7 operated with a direct current. The rest of the functionality is the same. Fig. 8 The 3e storage and retrieval machine is also used in the Fig. 5The arrangement shown is applicable. It should also be noted here that the voltage applied to the control coil is influenced by, or depends on, the supply voltage V 1 for the inverter W.

[0073] In the examples mentioned so far, the supply voltage V1 for the inverter W was used as a parameter for determining where the electrical energy generated during deceleration of the storage and retrieval machine 3, 3', 3a..3e is directed. However, this procedure is not mandatory. It is also conceivable to check whether the inverter W is electrically connected to the energy storage device C or not. For example, the switching state of the energy storage switching element S2 or the state of the supply network L1..L3, for example at the network access point of the storage system 1a..1c, can be evaluated for this purpose.

[0074] Electrical energy generated when the storage and retrieval machine 3, 3', 3a..3e decelerates can also fed back into the energy storage device C when the inverter W is electrically connected to the energy storage device C, and fed into a braking resistor R when the inverter W is electrically disconnected from the energy storage device C.

[0075] In particular, the controllable drive motor switching element S1 connect the drive motor M to the inverter W if the inverter W is electrically connected to the energy storage device C, and connect the drive motor M to the braking resistor R if the inverter W is electrically separated from the energy storage device C.

[0076] This results in a switching cascade. If the energy storage switching element S2 disconnects the energy storage device C from the inverter W, the drive motor M is subsequently also disconnected from the inverter W and connected to the braking resistor R instead.

[0077] In the Fig. 4 to 8 The energy storage device C is designed as a stationary energy storage device C and is connected to an inverter W. However, the energy storage device C could also be electrically connected to inverters W of several storage and retrieval machines 3, 3', 3a..3e (see also the Fig. 1 to 3 ).

[0078] The one in the Fig. 4 to 8The drive motor M shown is not restricted in terms of its function and could therefore serve the travel movement of the storage and retrieval machine 3, 3', 3a..3e, the lifting and lowering movement of the loading platform 10 or the retracting and extending movement of the load handling device 11. The drive motor M can also represent several or all drives of the storage and retrieval machine 3, 3', 3a..3e.

[0079] Finally, it should be noted that the scope of protection is determined by the patent claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0080] In particular, it is also noted that the devices depicted may in reality comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size. Reference symbol list

[0081] 1a..1cShelving storage system 2Storage location 3, 3', 3a..3eShelving unit 4..4", 4a..4ePower supply 5Row of shelves 6Shelf aisle 7Chassis 8Rail 9Mast 10Loading platform 11Load handling device 12Cabling 13General cargo 14Chassis 15Lift 16Mast 17Loading platform 18Deployment device CEnergy storage CTR1, CTR2Control GSupply circuit L1..L3Supply network MDrive motor RBrake resistor S1Drive motor switching element S2Energy storage switching element V1Supply voltage for the inverter V2Mains voltage of the electrical supply network WInverter

Claims

1. A method for operating a storage and retrieval unit (3, 3', 3a..3e), wherein the storage and retrieval unit (3, 3', 3a..3e) comprises an inverter (W) and a drive motor (M) connectable thereto for the storage and retrieval unit (3, 3', 3a..3e), and wherein the inverter (W) is, at least temporarily, electrically connected to an energy store (C), which is connected to an electrical supply network (L1..L3) via a supply circuit (G), characterized in that an electrical energy generated during the decelerating of the storage and retrieval unit (3, 3', 3a..3e) is fed back into the energy store (C) if a supply voltage (V1) for the inverter (W) is above a first supply voltage threshold value, and is fed into a braking resistor (R) if the supply voltage (V1) for the inverter (W) is below the first supply voltage threshold value or below a lower, second supply voltage threshold value.

2. The method according to claim 1, characterized in that a controllable drive motor switching element (S1) connects the drive motor (M) to the inverter (W) if the supply voltage (V1) for the inverter (W) is above the first supply voltage threshold value, and connects the drive motor (M) to the braking resistor (R) if the supply voltage (V1) for the inverter (W) is below the first supply voltage threshold value or below the lower, second supply voltage threshold value.

3. The method according to claim 2, characterized in that the drive motor switching element (S1) comprises a drive motor relay, or is configured as drive motor relay, and a switching contact of the drive motor relay connects the drive motor (M) to the inverter (W) if a control coil of the drive motor relay, which control coil acts on the switching contact and is arranged in a current path located between the switching contact and the energy store (C), is supplied with a voltage above a switch-on voltage of the drive motor relay and the drive motor relay is energized, and connects the drive motor (M) to the braking resistor (R) if the voltage at the control coil is below a switch-off voltage of the drive motor relay and the drive motor relay is released.

4. The method according to any one of the claims 1 to 3, characterized in that a controllable energy store switching element (S2) connects the inverter (W) to the energy store (C) if a line voltage (V2) of the electrical supply network (L1..L3) is above a first line voltage threshold value and / or if the energy store (C) is electrically connected to the electrical supply network (L1..L3), and disconnects the inverter (W) from the energy store (C) if the line voltage (V2) of the electrical supply network (L1..L3) is below the first line voltage threshold value or below a lower, second line voltage threshold value and / or if the energy store (C) is electrically disconnected from the electrical supply network (L1..L3).

5. A method for operating a storage and retrieval unit (3, 3', 3a..3e), wherein the storage and retrieval unit (3, 3', 3a..3e) comprises an inverter (W) and a drive motor (M) connectable thereto for the storage and retrieval unit (3, 3', 3a..3e), and wherein the inverter (W) is, at least temporarily, electrically connected to an energy store (C), which is connected to an electrical supply network (L1..L3) via a supply circuit (G), characterized in that an electrical energy generated during the decelerating of the storage and retrieval unit (3, 3', 3a..3e) is fed back into the energy store (C) if the inverter (W) is electrically connected to the energy store (C), and is fed into a braking resistor (R) if the inverter (W) is electrically disconnected from the energy store (C), and a controllable energy store switching element (S2) is provided, which connects the inverter (W) to the energy store (C) if a line voltage (V2) of the electrical supply network (L1..L3) is above a first line voltage threshold value and / or if the energy store (C) is electrically connected to the electrical supply network (L1..L3), and disconnects the inverter (W) from the energy store (C) if the line voltage (V2) of the electrical supply network (L1..L3) is below the first line voltage threshold value or below a lower, second line voltage threshold value and / or if the energy store (C) is electrically disconnected from the electrical supply network (L1..L3), wherein, in order to check whether or not the inverter (W) is electrically connected to the energy store (C), a switching state of the energy store switching element (S2) or a status of the electrical supply network (L1..L3) are evaluated.

6. The method according to claim 4 or 5, characterized in that the energy store switching element (S2) comprises an energy store relay, or is configured as energy store relay, and a switching contact of the energy store relay connects the inverter (W) to the energy store (C) if a control coil of the energy store relay, which control coil acts on the switching contact and is arranged in a current path located between the energy store (C) and the electrical supply network (L1..L3), is supplied with a voltage above a switching voltage of the energy store relay and the energy store relay is energized, and disconnects the inverter (W) from the energy store (C) if the voltage at the control coil is below the switching voltage of the energy store relay and the energy store relay is released.

7. A rack storage system (1a..1c), comprising a storage and retrieval unit (3, 3', 3a..3e), which comprises an inverter (W) and a drive motor (M) connectable thereto for the storage and retrieval unit (3, 3', 3a..3e), an energy store (C), which is, at least temporarily, electrically connected to the inverter (W), and a supply circuit (G), which is connected to an electrical supply network (L1..L3) and to the energy store (C), characterized by a drive motor switching element (S1), which is configured for connecting the drive motor (M) to the inverter (W) if a supply voltage (V1) for the inverter (W) is above a first supply voltage threshold value, and connecting the drive motor (M) to the braking resistor (R) if the supply voltage (V1) for the inverter (W) is below the first supply voltage threshold value or below a lower, second supply voltage threshold value.

8. The rack storage system (1a..1c) according to claim 7, characterized in that the energy store (C) is configured as a stationary energy store (C) and is, in particular electrically, connected to inverters (W) of multiple storage and retrieval units (3, 3', 3a..3e).

9. The rack storage system (1a..1c) according to claim 7 or 8, characterized in that the drive motor switching element (S1) comprises a drive motor relay, or is configured as drive motor relay, and the drive motor (M) is connectable to the inverter (W), or to the braking resistor (R), via a switching contact of the drive motor relay, and a control coil of the drive motor relay, which control coil acts on the switching contact, is arranged in a current path located between the switching contact and the energy store (C).

10. The rack storage system (1a..1c) according to any one of the claims 7 to 9, characterized by a controllable energy store switching element (S2), which is configured for connecting the inverter (W) to the energy store (C) if a line voltage (V2) of the electrical supply network (L1..L3) is above a first line voltage threshold value and / or if the energy store (C) is electrically connected to the electrical supply network (L1..L3), and disconnecting the inverter (W) from the energy store (C) if the line voltage (V2) of the electrical supply network (L1..L3) is below the first line voltage threshold value or below a lower, second line voltage threshold value and / or if the energy store (C) is electrically disconnected from the electrical supply network (L1..L3).

11. A rack storage system (1a..1c), comprising a storage and retrieval unit (3, 3', 3a..3e), which has an inverter (W) and a drive motor (M) connectable thereto for the storage and retrieval unit (3, 3', 3a..3e), an energy store (C), which is, at least temporarily, electrically connected to the inverter (W), and a supply circuit (G), which is connected to an electrical supply network (L1..L3) and to the energy store (C), characterized by a drive motor switching element (S1), which is configured for connecting the drive motor (M) to the inverter (W) if the inverter (W) is electrically connected to the energy store (C), and connecting the drive motor (M) to the braking resistor (R) if the inverter (W) is electrically disconnected from the energy store (C), and a controllable energy store switching element (S2), which is configured for connecting the inverter (W) to the energy store (C) if a line voltage (V2) of the electrical supply network (L1..L3) is above a first line voltage threshold value and / or if the energy store (C) is electrically connected to the electrical supply network (L1..L3), and disconnecting the inverter (W) from the energy store (C) if the line voltage (V2) of the electrical supply network (L1..L3) is below the first line voltage threshold value or below a lower, second line voltage threshold value and / or if the energy store (C) is electrically disconnected from the electrical supply network (L1..L3), wherein the rack storage system (1a..1c), in order to check whether or not the inverter (W) is electrically connected to the energy store (C), is further configured for evaluating a switching state of the energy store switching element (S2) or a status of the electrical supply network (L1..L3).

12. The rack storage system (1a..1c) according to claim 10 or 11, characterized in that the energy store switching element (S2) comprises an energy store relay, or is configured as energy store relay, and the inverter (W) is connectable to, and disconnectable from, the energy store (C) via a switching contact of the energy store relay, and a control coil of the second relay, which control coil acts on the switching contact, is arranged in a current path located between the energy store (C) and the electrical supply network (L1..L3).