EP4245923B1 - Electrically operated civil engineering machine and method for operating the machine - Google Patents

Description

The invention relates to an electrically operated civil engineering machine with a mobile carrier device, at least one civil engineering tool, at least one electric motor which is designed both to drive an actuating unit in a drive mode and to generate electrical energy in a recuperation mode, at least one internal rechargeable battery unit for storing electrical energy and for supplying the at least one electric motor with electrical energy, a supply device for supplying electrical energy from an external energy source for electrically operating the civil engineering machine and a circuit arrangement by means of which the at least one electric motor, the at least one battery unit and the supply device are connected to one another by line, according to the preamble of claim 1.

The invention further relates to a method for electrically operating a civil engineering machine with a mobile carrier device, at least one civil engineering tool, at least one electric motor which is designed both to drive an actuating unit in a drive mode and to generate electrical energy in a recuperation mode, at least one internal rechargeable battery unit for storing electrical energy and for supplying the at least one electric motor with electrical energy, a supply device for supplying electrical energy from an external energy source and a circuit arrangement by means of which the at least one electric motor, the at least one battery unit and the supply device are connected to one another by line, according to the preamble of claim 10.

Purely electrically powered civil engineering machines have long been out of service, for example EP 3 467 209 A1 and are used in particular at work sites where noise, vibrations and exhaust gases are undesirable, such as those that occur more frequently in civil engineering machines powered by combustion engines. Due to the high energy requirements of such electrically powered civil engineering machines, they have a supply device for supplying electrical energy from an external electrical energy source, which is also referred to as a power source, in particular an electrical power network. For this purpose, the provision of an appropriate electrical cable is necessary.

Furthermore, electrically operated civil engineering machines are also provided with a rechargeable battery unit, which serves in particular to supply the mobile civil engineering machine with sufficient electrical energy during movement or processing in which the electrical line connection is often disconnected.

The storage of electrical energy in an internal battery unit also allows additional electrical energy to be drawn from the internal battery unit to cover peak energy requirements during energy consumption peaks of the civil engineering machine, which cannot be fully covered by the normal energy supply via the supply device from the connected external power grid.

It is also known to design electric motors on a civil engineering machine in such a way that they can also be operated recuperatively to recover energy. In particular, when operating cable winches, with which loads can be raised and lowered, for example vertically or diagonally, the potential energy of the load can be converted back into electrical energy when lowering using an electric motor in recuperation mode. This reduces the energy requirement of the civil engineering machine and makes operation more economical and environmentally friendly overall.

For efficient operation of the civil engineering machine, it is essential that the energy is controlled and distributed as required. Basically, as with electrically powered vehicles, especially In motor vehicles with recuperative electric motors, energy distribution is provided by a central control system. Values relating to the energy requirements of the individual electrical consumers are transmitted to a central computer via appropriate sensors, and the computer then controls the energy supply via the supply device and the battery unit.

During operation of a civil engineering machine, large load changes can occur, which lead to short-term increases in energy consumption or to short-term amounts of energy that are generated recuperatively.

The invention is based on the object of specifying an electrically operated civil engineering machine and a method for operating the same, with which a particularly economical and efficient operation of the civil engineering machine is possible.

The object is achieved on the one hand by a civil engineering machine with the features of claim 1 and on the other hand by a method with the features of claim 10. Preferred embodiments of the invention are specified in the dependent claims.

The civil engineering machine according to the invention is characterized in that the circuit arrangement has an intermediate circuit with voltage-controlled power control and that the power control is implemented in a decentralized manner, with an independent control component being assigned to the at least one electric motor, the at least one battery unit and the supply device, which controls a supply or output of electrical energy from or into the intermediate circuit depending on a voltage in the intermediate circuit. The intermediate circuit can be an electrical conductor, in particular a busbar.

A basic idea of the invention is to move away from a central control system for power control or power management. This is achieved by providing a circuit arrangement with an intermediate circuit with voltage-controlled power control. An independent control component is assigned to the at least one electric motor, the at least one battery unit and the feed device. This control component is not controlled by a central control system. Rather, the individual independent control components determine the power consumption depending on a value measured in the intermediate circuit. Voltage from each control component independently supplies energy to the intermediate circuit or removes energy from the intermediate circuit. This decentralized power control enables the system as a whole to react very quickly to load changes with a sudden increase or decrease in energy requirements. Even large amounts of recuperatively generated energy that are required at short notice can be fed to electrical consumers, the internal battery unit or, if necessary, to the external power grid, provided this is possible.

In principle, the respective control components can be provided in a suitable position. According to a further development of the invention, it is particularly preferred that the control components are interposed between the intermediate circuit and the respectively assigned electric motor, the assigned battery unit or the assigned supply device. The control components can receive values for the current voltage in the intermediate circuit directly or via a corresponding measuring element. Each control component is provided with a control logic which specifies that energy is to be supplied to the intermediate circuit or removed from the intermediate circuit at a certain voltage value or at a certain time profile of the voltage values in the intermediate circuit, in order to supply electric motors or other electrical consumers with the required energy as required or, if necessary, to supply energy generated in a recuperation mode to the battery unit for storage.

A further preferred embodiment of the invention consists in that an excess energy consumption unit, in particular a brake chopper and/or an electrical consumer with an independent control component is provided and is connected to the intermediate circuit. The excess energy consumption unit, in particular a so-called brake chopper, can convert excess energy from recuperation, which is not required and cannot be stored, in particular into heat. The heat can be released into the environment, for example, if it cannot be used to heat the driver's cab. This can prevent overloading of the electrical system of the civil engineering machine and also the internal battery unit. In particular, the service life of a battery unit can be significantly impaired. if too much energy is fed into the battery unit in too short a time. Excess energy can also be fed to another electrical consumer in order to avoid overvoltage peaks, for example.

The intermediate circuit can basically be designed in any suitable way. According to one embodiment of the invention, it is particularly advantageous that the intermediate circuit is designed to conduct and distribute energy on a direct current basis. An intermediate circuit for conducting direct current allows for particularly good and fast energy distribution.

In particular when conducting and distributing the energy in the intermediate circuit as direct current, it is advantageous according to an embodiment variant of the invention that at least one control component comprises a DC/DC controller. Preferably, several or all control components can have a DC/DC controller. By means of such a controller, a direct voltage supplied to an input can be converted into a direct voltage with a higher, lower or inverted voltage level. Such DC/DC controllers are in particular self-commutated power converters.

When drawing electrical energy from an external alternating current network, it is advantageous according to a development of the invention that the supply device is designed to supply electrical energy from an alternating current source, with a current rectifier unit being provided on the supply device. This can in particular be a rectifier by means of which an alternating current or an alternating voltage can be converted into a direct current or a direct voltage.

A further advantageous embodiment of the invention is that the at least one electric motor is assigned an inverter unit which is designed to convert direct current or voltage into alternating current or voltage and vice versa. The inverter unit thus also represents a rectifier or inverter which can convert current and voltage in both directions. On the one hand, direct current from the intermediate circuit can be supplied to the electric motor as alternating current, while on the other hand, electrical energy generated in a recuperation mode of the electric motor can be fed from a Alternating current can be converted into direct current for supply to the intermediate circuit. When explaining the invention, reference is usually made to alternating current and direct current. In principle, reference could also be made to alternating voltage and direct voltage, since alternating current usually only occurs with alternating voltage and direct current only with direct voltage.

The actuating unit, which is driven by the electric motor that can also be operated recuperatively, can be any actuating unit on the civil engineering machine that releases energy during a braking process or a lowering process or something similar. This energy can be used to operate the electric motor in recuperation mode so that this kinetic and/or potential energy can be converted into electrical energy.

According to a preferred embodiment of the invention, it is provided that it is designed as a drilling device and that the at least one electric motor drives a rotary power head and/or a cable winch or any other consumer such as a hydraulic pump. The drilling device can in particular be an earth drilling device which can be used, for example, to create foundation piles in the ground. In particular on such a drilling device, especially when it is used for discontinuous drilling, for example with a drilling bucket, the drilling tool is frequently raised and lowered. In particular when lowering, an electric motor on the associated cable winch can regularly convert potential energy into electrical energy. This can significantly improve the energy efficiency of a civil engineering machine. It is also advantageous if at least two electric motors are provided.

The method according to the invention is characterized in that the circuit arrangement has an intermediate circuit with voltage-controlled power control, that the power control is carried out decentrally, wherein an independent control component is assigned to the at least one electric motor, the at least one battery unit and the feed device, and that by means of the independent control component, electrical energy is delivered from the at least one electric motor, which is connected to the at least one battery unit and the feed device, into the intermediate circuit or is fed to it from the intermediate circuit, depending on a voltage in the intermediate circuit.

The method can be used in particular with the civil engineering machine according to the invention described above. The advantages described above can be achieved in this way.

A preferred method variant of the invention consists in that excess electrical energy that cannot be used to operate the civil engineering machine and to charge the batteries is fed to an excess energy consumption unit, in particular a brake chopper. In recuperation mode, a large amount of electrical energy can be generated in the short term, particularly when lowering heavy loads. Feeding too much electrical energy to the battery unit can damage the battery unit or significantly reduce the service life of the battery unit. In such a case, it is expedient to feed unusable excess energy to a corresponding consumption unit, in particular a so-called brake chopper. This can consume and reduce the excess energy, for example by converting it into heat. The heat can be released into the environment if it cannot be used for other purposes. In principle, energy consumption by the brake chopper is a measure that should be avoided as far as possible and only used when necessary. In principle, the construction machine can be operated in such a way that the energy generated is used in the battery unit or by electrical consumers and/or a power outage, for example by lowering a cable winch, is controlled in such a way that the lowering speed is reduced and the energy generated is distributed over a longer period of time.

A particularly good and fast energy distribution in the system can be achieved according to a process variant by conducting and distributing the electrical energy as direct current in the intermediate circuit.

According to a further method variant, it is preferred that electrical energy is supplied as alternating current from the external energy source via the supply device, wherein a current rectifier unit is arranged on the supply device, by which the alternating current is converted into direct current. Converter units can also be provided on the control components, so that it is ensured that the desired type of current, in particular a direct current is supplied or removed and the desired voltage level is regulated.

In a corresponding manner, according to a further development of the invention, it is preferred that the at least one electric motor is assigned an inverter unit, by means of which the direct current from the intermediate circuit is converted into alternating current in the drive mode and, conversely, an alternating current generated by the electric motor in the recuperation mode is converted into direct current. In this case, the supply and discharge of electrical energy to and from the intermediate circuit takes place exclusively as direct current. If required, a corresponding conversion into or from alternating current is provided. This enables reliable and rapid energy distribution.

Fig. 1

eine Seitenansicht einer erfindungsgemäßen Tiefbaumaschine; und

Fig. 2

eine schematische Darstellung einer Schaltungsanordnung nach der Erfindung mit möglichen Komponenten.

The invention is explained in more detail below using preferred embodiments, which are shown schematically in the drawings. In the drawings:

Fig.1

a side view of a civil engineering machine according to the invention; and

Fig.2

a schematic representation of a circuit arrangement according to the invention with possible components.

A civil engineering machine 10 according to the invention with a carrier device 12 is shown in Fig.1 shown. The carrier device 12 comprises a crawler chassis as an undercarriage 14, on which a superstructure 16 is rotatably mounted. A control 60 for the civil engineering machine 10 is located in an operator's cabin of the superstructure 16. A mast 20 can be adjustably mounted on the superstructure 16 via a linkage mechanism 18, which mast has a substantially vertical position during operation.

According to the embodiment shown, the mast 20 can be designed as a leader 21 with a linear guide 24 on its front side. A work carriage 38 with a rotary drilling drive 36 can be mounted so that it can move vertically along the linear guide 24. This allows the civil engineering machine 10 to be designed as a drilling device. The drawing shows an upper position of the rotary drilling drive 36 and a lower position with broken lines.

A cable 40 can be guided over a mast head 22 at the upper end of the mast 20, at one end of which a preferably telescopic Kelly bar 32 with an exemplary auger 34 can be provided for forming a civil engineering tool 30. The Kelly bar 32 can be guided through a sleeve-shaped drive wheel of the rotary drilling drive 36 on the work carriage 38, so that a torque can be transmitted from the rotary drilling drive 36 to the Kelly bar 32 via driver strips (not shown). The auger 34 can be arranged at the lower end of the Kelly bar 32 for creating a borehole in the ground. The drilling tool can basically be designed in any way and in particular can have a auger 34 or a drilling bucket.

From the Kelly bar 32, the cable 40 can be guided over pulleys 26 on the mast head 22 along the mast 20 to a cable winch 46 in the upper carriage 16. According to the invention, the cable winch 46 is driven by an electric motor 50, which can also be operated in a recuperation mode. The Kelly bar 32 with the auger 34 can be raised and lowered via the cable winch 46 using the cable 40. When lowering, potential energy can be converted into electrical energy by the electric motor 50 and delivered to an intermediate circuit, which is described in more detail below.

The working carriage 38 with the rotary drilling drive 36 can be pulled upwards via an actuator 28 with a winch on the mast 20 using a further adjusting cable 29. By driving the actuator 28 in the opposite direction, the working carriage 38 with the rotary drilling drive can also be lowered downwards. The rotary drilling drive can be formed by a power rotary head 36 with at least one further electric motor. The actuator 28 can also be equipped with an electric motor (not shown), which can also be operated in recuperation mode. The working carriage 38 with the rotary drilling drive 36 can also be regarded as part of the civil engineering tool 30.

In the embodiment shown, a force measuring device 62 is preferably arranged on a deflection roller 26 on the mast head 22. The force measuring device 62 can, for example, be designed as a force measuring bolt, by means of which a cable tensile force on the cable 40 can be detected. The force measuring device 62 is connected to the control 60 on the upper carriage 16.

The at least one electric motor 50 for operating the cable winch 46 and preferably also the further electric motor for operating the actuator 28 designed as a winch are controlled via the controller 60. The electric motor 50 can be controlled by the controller 60.

In Fig.2 a circuit arrangement 70 according to the invention is shown schematically with an intermediate circuit 72, which is designed in particular as a direct current-operated DC link, for example with a defined voltage of 750 volts. The intermediate circuit 72 can be connected as a main power supply to a supply device 80, which is connected to an energy source 82 via a detachable connection 81. The energy source 82 can in particular be an alternating current network.

For further energy supply, the intermediate circuit 72 is connected to at least one further battery unit 58, which is rechargeable. The at least one battery unit 58 can be charged via the intermediate circuit 72. Energy from the external energy source 82 or electrical energy generated recuperatively on the civil engineering machine 10 can be used for this purpose.

In Fig.2 Furthermore, at least one electric motor 50 is shown schematically, which is connected to the Fig.2 A cable winch (not shown) can raise and lower a schematically indicated civil engineering tool 30 along a mast. For lifting, the electric motor 50 for driving the cable winch is supplied with electrical energy from the intermediate circuit 72.

Furthermore, when the tool device 30 is lowered in a recuperation mode of the electric motor 50, potential energy can be converted into electrical energy. This electrical energy of the electric motor 50 is fed to the intermediate circuit 72 via an intermediate inverter unit 52, which can convert alternating current into direct current and vice versa. This electrical energy can be fed from the intermediate circuit 72 to the at least one battery unit 58 or at least one further electrical consumer 64. The internal battery unit 58 can in principle be designed to be replaceable, in particular as a removable accumulator. The further electrical consumer can also be an electric motor, a heating coil or another electrically operated component.

According to the invention, the supply and discharge of electrical energy are not controlled by a central control system. Rather, the supply device 80, the at least one battery unit 58, the electric motor 50 and the at least one electrical consumer 64, as well as a brake chopper 66 (to be described later) are each assigned an independent control component. This can be installed directly in the respective unit. The control component can detect a voltage in the intermediate circuit 72. Depending on a stored control logic in each control component, electrical energy can be supplied or discharged depending on the current voltage value in the intermediate circuit 72 or a course of the voltage value. This enables a faster response to sharply increasing energy consumption or large amounts of energy that arise in the short term compared to a central control system.

If electrical energy that is generated recuperatively cannot be stored in the at least one battery unit 58 in the circuit arrangement 70 or supplied to another component for use, this excess energy can be supplied to a brake chopper 66, which represents an example of a surplus energy consumption unit. It converts this excess energy into heat, for example.

In addition, the supply device 80 can also be assigned an inverter unit, particularly in the case of the supply of alternating current from the external energy source 82. This ensures that only direct current is supplied to the intermediate circuit 72 in the exemplary embodiment shown.

Claims (14)

1. Electrically operated civil engineering machine (10) comprising

   - a mobile carrier device (12),

   - at least one civil engineering tool (30),

   - at least one electric motor (50) configured for both driving an actuator in a drive mode and for generating electrical energy in a recuperation mode,

   - at least one internal rechargeable battery unit (58) for storing electrical energy and for supplying the at least one electric motor (50) with electrical energy,

   - feeding means (80) for supplying electrical energy from an external energy source (82) for electrically operating the civil engineering machine (10), and

   - a circuit arrangement (70) by means of which the at least one electric motor (50), the at least one battery unit (58) and the feeding means (80) are line-connected to each other,

   characterized in that

   - the circuit arrangement (70) has an intermediate circuit (72) with voltage-controlled power control, and

   - the power control is decentralized wherein an independent control component is respectively assigned to the at least one electric motor (50), the at least one battery unit (58) and the feeding means (80) which is configured to respectively control a supply or an output of electric energy from or to the intermediate circuit (72) depending on a voltage in the intermediate circuit (72).
2. Electrically operated civil engineering machine (10) according to claim 1, characterized in that
   the control components are interposed between the intermediated circuit (72) and the respectively assigned electric motor (50), the assigned battery unit (58) or the assigned feeding means (80).
3. Electrically operated civil engineering machine (10) according to claim 1 or 2, characterized in that
   an excess energy consumption unit, in particular a break chopper (66) and/or an electrical consumer (64) with an independent control component is provided and line-connected to the intermediate circuit (72).
4. Electrically operated civil engineering machine (10) according to one of the claims 1 to 3,
   characterized in that
   the intermediate circuit (72) is configured to conduct and distribute direct current.
5. Electrically operated civil engineering machine (10) according to one of the claims 1 to 4,
   characterized in that
   at least one control component comprises a DC/DC controller.
6. Electrically operated civil engineering machine (10) according to one of the claims 1 to 5,
   characterized in that
   the feeding means (80) is configured to supply electrical energy from an alternating current source, wherein a current rectifier unit is arranged on the feeding means (80).
7. Electrically operated civil engineering machine (10) according to one of the claims 1 to 6,
   characterized in that
   an inverter unit (52) is assigned to the at least one electric motor (50) configured to convert direct current into alternating current and vice versa.
8. Electrically operated civil engineering machine (10) according to one of the claims 1 to 7,
   characterized in that

   the latter one being configured as a boring machine and

   the at least one electric motor (50) drives a power-rotary head (36) and/or a rope winch (46).
9. Electrically operated civil engineering machine (10) according to one of the claims 1 to 8,
   characterized in that
   there are at least two electric motors (50) provided.
10. Method for electrically operating a civil engineering machine (10), in particular according to one of the claims 1 to 9, comprising:

    - a mobile carrier (12),

    - at least one civil engineering tool (30),

    - at least one electric motor (50) configured to both drive an actuator in a drive mode and generate electrical energy in a recuperation mode,

    - at least one internal rechargeable battery unit (58) for storing electrical energy and for supplying the at least one electric motor (50) with electrical energy,

    - feeding means (80) for supplying electrical energy from an external energy source (82), and

    - a circuit arrangement (70) by means of which the at least one electric motor (50), the at least one battery unit (58) and the feeding means (80) are line-connected to each other,

    characterized in that

    - the circuit arrangement (70) has in intermediate circuit (72) with voltage controlled power control,

    - the power control is decentralized wherein an independent control component is respectively assigned to the at least one electric motor (50), the at least one battery unit (58) and the feeding means (80), and

    - electrical energy is released respectively dependent on a voltage in the intermediate circuit (72) from the at least one electric motor (50), the at least one battery unit (58) and the feeding means (80) by means of the independent control component into the intermediate circuit (72) or supplied to from the intermediate circuit (72).
11. Method according to claim 10,
    characterized in that
    electrical excess energy, which cannot be used to operate the civil engineering machine (10) and charge the battery unit (58), is supplied to an excess energy consumption unit, in particular a break chopper (66).
12. Method according to claim 10 or 11,
    characterized in that
    in the intermediate circuit (72) the electric energy is conducted and distributed as direct current.
13. Method according to one of the claims 10 to 12,
    characterized in that
    electrical energy is supplied as alternating current from the external energy source (82) via the feeding means (80), wherein a current rectifier unit is arranged on the feeding means (80) by means of which the alternating current is converted into direct current.
14. Method according to claim 12 or 13,
    characterized in that
    an inverter unit is assigned to the at least one electric motor (50) by means of which the direct current from the intermediate circuit (72) is converted into alternating current in the drive mode and reversely an alternating current generated by the electric motor (50) is converted into direct current in the recuperation mode.

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