Construction machine with DC voltage on-board power supply system

Abstract

The invention relates to a construction machine comprising a lower carriage, an upper carriage mounted rotatably on the lower carriage and an on-board electricity supply system. The on-board electricity supply system comprises a DC voltage circuit and at least one electrical consumer and at least one electrical energy source and / or interface for connecting an external energy source, which are connected to one another via the DC voltage circuit. According to the invention, the DC voltage circuit extends on the upper carriage and lower carriage and comprises an upper carriage circuit and a lower carriage circuit, which are connected to one another via a DC transmission extending between the upper carriage and lower carriage.

Description

[0001] Construction machine with DC on-board power supply

[0002] The present invention relates to a construction machine according to the preamble of claim 1.

[0003] In recent years, the trend has increasingly shifted toward the electrification of construction machinery to reduce CO2 emissions and increase energy security. As a result of this electrification, construction machinery with battery-electric or hybrid drive systems is increasingly being used.

[0004] The typical structure of a known battery-electric or hybrid construction machine 1 is shown schematically in Figure 1. The construction machine 1 has an electrical energy source in the form of an electrical energy storage device 40, which is connected to any number of electrical consumers 30 via a DC voltage on-board network 20. As electrical consumers 30, the construction machine 1 can have several electric drive trains, each with at least one electric motor 32, which, for example, drives a pump distribution gear for supplying hydraulic actuators and / or motors. A further electrical consumer 30 can be a possibly present low-voltage on-board network 34. The construction machine 1 can have further power electronics, for example a DC / DC converter 38, which converts the DC intermediate circuit voltage into a low voltage (e.g.24V) for the low-voltage vehicle electrical system 34, or inverters which convert the DC link voltage into an AC voltage for operating one or more electric motors 32.

[0005] The construction machine 1 can have a charging interface for connecting an external energy source. Figure 1 shows an example of an alternating current (AC) charging interface 52 for connecting an external three-phase electrical network 60, wherein the AC voltage is converted into a suitable DC voltage for the DC link 20 via an AC / DC converter 54 (for example, a charger or on-board charger (OBC)).

[0006] In electro-hydraulic drive architectures, the on-board electrical system is typically limited to an electric drive train, the main electric drive. This drives one or more hydraulic pumps via a transfer case. If the respective load is driven directly by an electric motor, as shown in Figure 1, the DC voltage on-board electrical system 20 extends across the entire construction machine 1.

[0007] In the example shown in Figure 1, the construction machine 1 can have a primary energy source 42 (hybrid drive) in parallel with the energy storage unit 40. The primary energy source 42 can comprise an internal combustion engine 43 (e.g., a diesel engine) that drives an electric generator 44, whose output AC voltage is converted by an AC / DC converter 45 into a suitable DC voltage for the DC intermediate circuit 20. The DC voltage on-board network 20 connects the various electrical energy sources to the various electrical consumers, thus forming a DC intermediate circuit 20. In many construction machines, the DC intermediate circuit 20 forms a high-voltage on-board network, which is designed, for example, for DC voltages of 60V to 1500V.

[0008] A number of construction machines have an undercarriage and a rotating uppercarriage mounted on the undercarriage. The undercarriage can be stationary or mobile. Examples of the latter include crawler cranes, mobile cranes, hydraulic excavators, duty cycle excavators, truck-mounted concrete pumps (in which case the uppercarriage typically includes a concrete placing boom), or civil engineering machines such as rotary drilling rigs, trench cutters or grabs, or vibratory pile drivers. Construction machines with crawler tracks, in particular, usually have hydraulic travel drives. For this purpose, a diesel engine is typically installed in the uppercarriage, which drives a pump distribution gearbox that supplies the hydraulic travel drives in the undercarriage. Alternatively, it is known to supply an electric motor via a generator connected to the diesel engine, which in turn drives a pump distribution gearbox that supplies the hydraulic travel drives.

[0009] The present invention is based on the object of enabling further electrification of construction machines with a rotating superstructure.

[0010] According to the invention, this object is achieved by a construction machine having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0011] Accordingly, a construction machine is proposed which comprises an undercarriage, a superstructure rotatably mounted on the undercarriage, and an on-board electrical system. The on-board electrical system can be understood, in particular, to refer to all of the electrical components of the construction machine. The on-board electrical system comprises a DC voltage circuit, at least one electrical consumer, and at least one electrical energy source and / or at least one electrical interface for connecting an external energy source. The at least one electrical consumer is connected to the at least one electrical energy source and / or the at least one electrical interface via the DC voltage circuit.The on-board electrical system can also comprise, for example, a low-voltage on-board electrical system, at least one sensor for detecting a parameter of the construction machine or a work process parameter, at least one control unit for controlling one or more components, at least one display element and / or at least one input unit. According to the invention, the DC voltage circuit extends to both the superstructure and the undercarriage and comprises an uppercarriage circuit arranged in the superstructure and an undercarriage circuit arranged in the undercarriage. For this purpose, the DC voltage circuit comprises a DC transmission which extends between the superstructure and the undercarriage and connects the uppercarriage circuit to the undercarriage circuit, i.e. connects them electrically.

[0012] The solution according to the invention therefore extends the DC on-board power supply, which is usually located in the superstructure, to the undercarriage, with direct current being transmitted between the superstructure and undercarriage via the DC transmission. This makes it possible, for example, to provide a purely electric drive system in the undercarriage, which is powered by one or more energy sources from the superstructure. This eliminates the need for additional components such as combustion engines and generators in the undercarriage.

[0013] Extending the DC circuit to the undercarriage and uppercarriage enables electrification of the construction machine with fewer electronic components and greater flexibility in the arrangement of components and interfaces. Furthermore, the required cable lengths can be reduced and unnecessary interfaces eliminated. For example, the DC circuit extending across the entire construction machine now makes it possible to provide a DC charging interface on the undercarriage to charge an energy storage unit in the uppercarriage. The fed-in energy can be made available to energy storage units and / or consumers throughout the construction machine via the DC transmission.

[0014] In the following, the terms “direct current” and “alternating current” or “direct voltage” and “alternating voltage” are also abbreviated to “DC” and “AC” (for example “DC circuit” instead of “direct voltage circuit” or “DC transmission” instead of “direct current transmission”). In one possible embodiment, the superstructure comprises at least one electrical energy source, wherein the electrical energy source is an electrical energy storage device. This can be a single storage device or a combination of several energy storage devices. One or more electrical consumers of the construction machine can be supplied with energy via the electrical energy storage device. The at least one electrical energy storage device is preferably a battery-supported energy storage device.

[0015] In a further possible embodiment, the superstructure comprises at least one electrical energy source, wherein the electrical energy source is a primary energy source. In contrast to an electrical energy storage device, the primary energy source itself generates electrical energy and can, for example, comprise an internal combustion engine (e.g. a diesel engine or a gasoline engine). This can be connected to an electrical generator for generating electricity, the latter being coupled to the DC voltage circuit in particular via an AC / DC converter in order to provide the required DC voltage. Alternatively, the primary energy source can comprise a fuel cell, which can optionally be coupled to the DC voltage circuit via a DC / DC converter. Other primary energy sources are also conceivable, such as a solar system or a wind turbine.The superstructure can have several different primary energy sources, such as an internal combustion engine and a fuel cell.

[0016] Of course, the superstructure can comprise several electrical energy sources, for example one or more electrical energy storage units and one or more of the aforementioned primary energy sources, in any combination and number.

[0017] In a further possible embodiment, the superstructure comprises at least one electrical consumer, which can be supplied with power from an electrical energy source also arranged in or on the superstructure via the superstructure circuit. Alternatively or additionally, the undercarriage can comprise at least one electrical consumer, which can be supplied with power from an electrical energy source arranged in or on the superstructure via the superstructure circuit, the direct current transmission, and the undercarriage circuit.

[0018] Through direct current transmission between the uppercarriage and undercarriage, any electrical consumers in the uppercarriage and / or the undercarriage can be supplied by the uppercarriage's electrical energy sources, for example, an electric drive train for a work function of the uppercarriage and / or an electric travel drive in the undercarriage. Furthermore, energy transfer between electrical energy storage units in the uppercarriage and electrical energy storage units in the undercarriage is possible, for example, to charge an empty energy storage unit via another, fuller energy storage unit.

[0019] In another possible embodiment, the undercarriage comprises at least one electrical energy source, wherein the electrical energy source is an electrical energy storage device. The previous statements regarding the possible configurations of the electrical energy storage device of the superstructure apply analogously.

[0020] In a further possible embodiment, the undercarriage comprises at least one electrical energy source, wherein the electrical energy source is a primary energy source. The previous statements regarding a primary energy source of the superstructure also apply if the undercarriage has a primary energy source. The previous statements regarding the possible configurations of the primary source (as well as the possible combinations of energy storage device(s) and primary energy source(s)) of the superstructure apply analogously.

[0021] In a preferred embodiment, the undercarriage does not have its own primary energy source or, in general, its own electrical energy source. In this case, all electrical consumers of the undercarriage (in particular, one or more electric traction motors) are supplied via direct current transmission from one or more electrical energy sources of the superstructure.

[0022] In a further possible embodiment, it is provided that the undercarriage comprises at least one electrical consumer which can be supplied with energy via the undercarriage from an electrical energy source likewise arranged in or on the undercarriage. Alternatively or additionally, the uppercarriage can comprise at least one electrical consumer which can be supplied with energy from an electrical energy source arranged in or on the undercarriage via the undercarriage circuit, the direct current transmission and the uppercarriage circuit. Due to the direct current transmission between the uppercarriage and undercarriage, any electrical consumers in the uppercarriage and / or in the undercarriage can be supplied by electrical energy sources of the undercarriage, for example an electric drive train for a work function of the uppercarriage and / or an electric travel drive in the undercarriage.In addition, energy transfer between electrical energy storage units in the uppercarriage and electrical energy storage units in the undercarriage is possible.

[0023] In a further possible embodiment, the undercarriage comprises an electric drive with at least one electric drive motor, which can be supplied with power via the superstructure circuit, the direct current transmission, and the undercarriage circuit from an electrical energy source arranged in the superstructure. Optionally, the electric drive can also be supplied with power via the undercarriage circuit from an electrical energy source of the undercarriage. The power can be supplied by energy sources of the superstructure and the undercarriage in parallel. Alternatively, a control unit can be provided which, depending on the operating state and / or user input, supplies the electric drive either from the superstructure and / or the undercarriage.

[0024] In a further possible embodiment, the undercarriage comprises at least one electrical consumer in the form of an electric traction motor, wherein the electric traction motor preferably drives a wheel axle or a crawler carrier of the undercarriage. In the case of an undercarriage with crawler tracks, each crawler carrier can be driven by at least one separate electric traction motor.

[0025] In a further possible embodiment, it is provided that the at least one electric traction motor is configured to generate energy in recuperation mode (e.g. during braking of the construction machine), which energy can be fed into the DC voltage circuit. For example, the at least one electric traction motor can be configured to supply at least one electrical consumer arranged in the undercarriage and / or at least one electrical energy storage device arranged in the undercarriage with energy via the undercarriage circuit in recuperation mode. Alternatively or additionally, the at least one electric traction motor can be configured to supply at least one electrical consumer arranged in the superstructure and / or at least one electrical energy storage device arranged in the superstructure with energy via the undercarriage circuit, DC transmission and superstructure circuit in recuperation mode.

[0026] Regardless of the specific embodiment, the construction machine can preferably comprise a control unit which is configured to control the energy flows between the upper and lower carriages accordingly, for example to supply energy from an energy storage device and / or an energy source to a specific electrical consumer and / or to provide energy generated via an electric travel drive to an electrical energy storage device and / or an electrical energy source in the aforementioned recuperation mode.

[0027] In another possible embodiment, the superstructure includes at least one electrical consumer in the form of a low-voltage electrical system. The latter can be, for example, a 12V electrical system or a 24V electrical system, although an electrical system with any other voltage can also be provided. It is also conceivable for the construction machine to include multiple low-voltage electrical systems with different voltages, for example, a 12V electrical system and a 24V electrical system.

[0028] Alternatively or additionally, the superstructure can comprise at least one electrical consumer in the form of an electric motor, which serves, for example, to drive a hydraulic pump or a pump distribution gear (e.g., for supplying luffing and telescoping cylinders in a mobile crane, one or more cable winches, one or more hydraulic cylinders in a hydraulic excavator, etc.), an actuator, or a cooling device of the construction machine. The superstructure can comprise several such electrical consumers or electric drive trains, in any number and combination of the aforementioned functions.

[0029] In another possible embodiment, the undercarriage includes an electrical interface for connecting an external power source. The external power source can be, for example, an external power grid (e.g., a three-phase grid), a generator, or an external energy storage device. In principle, any type of external power supply capable of providing energy in the form of AC or DC is suitable.

[0030] At least one electrical consumer or energy storage device located in the superstructure can be supplied with energy via the electrical interface, the undercarriage circuit, the direct current transmission, and the superstructure circuit. Alternatively or additionally, at least one electrical consumer or energy storage device located in the undercarriage can be supplied with energy via the electrical interface and the undercarriage circuit. In particular, one or more electrical energy storage devices of the construction machine can be charged via the electrical interface. Direct operation or direct supply of electrical consumers of the construction machine is also possible.

[0031] The electrical interface is preferably a direct current charging interface or DC charging interface. Thanks to the solution according to the invention, this can now advantageously be arranged on the undercarriage, for example on a crawler support of the undercarriage. During mains operation, the movements of the undercarriage are generally smaller than on the superstructure (e.g. during a superstructure rotation), making it easier to connect the external power supply. In particular, if the charging interface is arranged on the superstructure, a plugged-in charging cable would move with a rotation of the superstructure or drag on the ground and thus possibly be damaged. Energy fed in via the DC charging interface can be made available to the direct voltage circuit. This also has the advantage over AC charging interfaces that no machine-side chargers such as on-board chargers (OBCs) are required.

[0032] In addition to the electrical charging interface on the undercarriage, the superstructure can also have another electrical charging interface (a DC charging interface or an AC charging interface). It is also conceivable for the undercarriage to comprise multiple electrical charging interfaces, for example, a DC charging interface and an AC charging interface. Alternatively, only the superstructure can have one or more electrical charging interfaces. In the case of an AC charging interface, this is preferably connected to the DC circuit (i.e., depending on the arrangement on the superstructure or undercarriage, to the superstructure or undercarriage circuit) via an AC / DC converter, in particular via an OBC.

[0033] In a further possible embodiment, the direct current transmission comprises a slip ring connection with a first slip ring contact connected to the undercarriage circuit and a second slip ring contact connected to the superstructure circuit. The DC slip ring connection preferably comprises a first slip ring body connected to the undercarriage circuit and a second slip ring body connected to the superstructure circuit. The slip ring connection ensures the direct current or DC transmission between the superstructure and undercarriage whatever the rotational position of the superstructure relative to the undercarriage. The DC transmission therefore remains intact even when the superstructure rotates and at any angular position. The DC slip ring connection is preferably arranged on or in a rotary connection between the superstructure and the undercarriage of the construction machine.The slewing ring preferably comprises a slewing mechanism with at least one hydraulic or electric rotary drive. The latter preferably represents an electrical consumer (or, in the case of a hydraulic rotary drive, the electric motor that drives the associated hydraulic pump or pump distribution gear) that is supplied via the DC circuit.

[0034] In another possible embodiment, the direct current transmission is configured for bidirectional direct current transmission between the undercarriage circuit and the superstructure circuit. This allows direct current to be transmitted both from the superstructure to the undercarriage and vice versa. This allows electrical energy sources and electrical energy sinks, or consumers, to be flexibly arranged on the construction machine and distributed as desired between the undercarriage and superstructure.

[0035] In another possible embodiment, the DC circuit is a high-voltage circuit. This can mean, in particular, that the DC voltage in the DC circuit can be between 60V and 1500V, although higher voltages are also conceivable in principle. Alternatively, the DC circuit can be designed for DC voltages of less than 60V, for example, in smaller construction machines.

[0036] In general, the DC voltage circuit can comprise at least one power electronics component, for example one or more frequency converters or AC / AC converters, inverters or DC-AC converters, rectifiers or AC / DC converters, switching regulators, DC / DC converters and / or power converters or switching power supplies.

[0037] The DC circuit forms, in particular, a DC intermediate circuit. Further features, details, and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. They show:

[0038] Figure 1 : a schematic representation of the electrical system of a construction machine known from the prior art; and

[0039] Figure 2: a schematic representation of the electrical system of the construction machine according to the invention according to an embodiment.

[0040] Figure 1 shows a schematic representation of the on-board electrical system of an example of a known construction machine 1 and has already been described above. In this example, no superstructure is present, and the electrical loads 30 are all supplied with energy from the available electrical energy sources via a DC voltage circuit 20. In this example, a primary energy source 42, an electrical energy storage device 40, and an external energy source 60, which is connected to the DC voltage circuit 20 via an electrical AC interface 52 and an AC / DC converter 54, are present.

[0041] Figure 2 schematically shows the electrical system of a preferred embodiment of the construction machine 10 according to the invention. In the embodiment considered here, the construction machine 10 comprises an undercarriage 12 with an electric travel drive and a superstructure 14 rotatably mounted on the undercarriage 12. The system boundaries of the undercarriage 12 and superstructure 14 are indicated by dashed boxes.

[0042] Components that have the same reference numerals as components in Figure 1 represent the same components or components with the same function. In particular, the components 30, 42 not specified in more detail in Figure 2 can have the same subcomponents as those in Figure 1. The relevant statements at the beginning of the description therefore also apply to the components in Figure 2 (e.g. in relation to the exemplary embodiment of the primary energy source 42 with combustion engine 43, generator 44 and AC / DC converter 45, the exemplary embodiment of the electrical consumer 30 with DC / DC converter 38 and low-voltage on-board network 34 and / or the exemplary embodiment of the electrical consumer 30 with DC / AC converter 36 and electric motor 32).

[0043] The superstructure 14 of the illustrated embodiment of the construction machine 10 according to the invention comprises a plurality of electrical consumers 30. At least one of these electrical consumers 30 can comprise an electric motor 32 that drives a pump distribution gear to supply one or more hydraulic actuators (not shown). Alternatively, the corresponding work functions can be driven directly by electric actuators (e.g., an electric rotary drive for a slewing gear of the superstructure 14, an electric winch motor, and / or an electric linear drive for adjusting a construction machine component). At least one electrical consumer 30 can comprise or represent a low-voltage on-board power supply 34 (e.g., a 24V on-board power supply).

[0044] In the exemplary embodiment schematically illustrated here, the superstructure 14 comprises two electrical energy sources: an electrical energy storage device 40 (for example, a battery-supported energy storage system) and a primary energy source 42 (for example, an arrangement according to Fig. 1 with an internal combustion engine 43 or an arrangement with one or more fuel cells). These electrical energy sources 40, 42 and consumers 30 are connected to one another via a DC voltage circuit 20, which, in the exemplary embodiment discussed here, represents a high-voltage DC network designed, for example, for DC voltages in the range of 60-1500 V.The DC voltage circuit 20 preferably comprises corresponding power electronic components such as a DC / AC converter 36 for supplying an electric motor 32, a DC / DC converter 38 for supplying a low-voltage on-board network 34 and / or an AC / DC converter 45 for connecting a generator 44 of a primary energy source 42.

[0045] In the exemplary embodiment shown here, the undercarriage 12 also has a plurality of electrical consumers 30 in the form of electric traction motors. The electric traction motors 30 can be used to drive crawler supports of a crawler track of the undercarriage 12. In order to be able to supply the electric traction motors 30 in the undercarriage 12 with DC current from the DC voltage circuit 20, this extends from the superstructure 14 into the undercarriage 12 via a DC transmission 24 (this is shown schematically in Figure 2 as box 24 and could also be referred to as a DC voltage connection). This is designed, in particular, in accordance with the design of the DC voltage circuit 20 for a DC voltage of 60-1500 V. The part of the DC voltage circuit 20 located in the superstructure 14 is referred to herein as the superstructure circuit 21 and is schematically illustrated in Figure 2 by a box 21.The part of the DC voltage circuit 20 located in the undercarriage 12 is referred to herein as the undercarriage circuit 22 and is schematically illustrated in Figure 2 by a box 22. The superstructure circuit 21 is connected to the undercarriage circuit 22 via the DC transmission 24.

[0046] Furthermore, as indicated in Figure 2, the construction machine 10 can have an electrical charging interface 50 on the undercarriage 12 for connecting an external energy source 60. The interface 50 is preferably a DC charging interface for feeding DC energy into the DC voltage circuit 20. This eliminates the need for additional components such as an OBC.

[0047] Via the DC transmission 24, direct current can be transmitted from the superstructure circuit 21 to the undercarriage circuit 22 or vice versa (bidirectional DC transmission). The corresponding energy flows can be controlled by a control unit (not shown). The DC transmission 24 between the sections of the construction machine 10 that rotate relative to one another (i.e., between the undercarriage 12 and the superstructure 14) can be achieved by means of DC slip rings (not shown).

[0048] The inventive machine configuration with DC transmission 24 between the upper and lower carriages 12, 14 offers several advantages with regard to the electrification of construction machines: • Power electronic components in the undercarriage 12 of the construction machine 10 can be supplied. This enables, for example,

[0049] - electrification of traction drives;

[0050] - a reduction in cable lengths and additional AC slip ring transmitters by setting up a local DC intermediate circuit in the undercarriage 12 (avoiding unnecessary interfaces).

[0051] • DC charging interfaces 50 are possible on the undercarriage 12 (e.g., on a crawler carrier). This allows the fed-in energy to be made available to the DC voltage on-board network 20 in the undercarriage and superstructure 12, 14 via the DC transmission 24.

[0052] - Charging interfaces are particularly suitable on the undercarriage 12 or a crawler carrier, since the range of movement on the undercarriage 12 is smaller than on the superstructure 14 during mains operation.

[0053] - DC charging interfaces 50 also offer the advantage that no machine-side chargers 54 (e.g. on-board charger, OBC) are required.

[0054] List of reference symbols:

[0055] 1 construction machine (state of the art)

[0056] 10 construction machines

[0057] 12 undercarriage

[0058] 14 superstructure

[0059] 20 DC circuit

[0060] 21 Uppercar circle

[0061] 22 Undercarriage circuit

[0062] 24 Direct current transmission

[0063] 30 Electrical consumer

[0064] 32 electric motor

[0065] 34 Low-voltage on-board network

[0066] 36 DC / AC converters

[0067] 38 DC / DC converter Electrical energy storage Primary energy source Combustion engine Electric generator AC / DC converter DC charging interface AC charging interface AC / DC converter / OBC External energy source

Claims

Patent claims 1. Construction machine (10) comprising an undercarriage (12), an uppercarriage (14) rotatably mounted on the undercarriage (12) and an on-board electrical system which comprises a DC voltage circuit (20) and at least one electrical consumer (30) and at least one electrical energy source (40, 42) and / or interface (50) for connecting an external energy source (60), which are connected to one another by the DC voltage circuit (20), characterized in that the DC voltage circuit (20) extends to the uppercarriage (14) and the undercarriage (12) and comprises an uppercarriage circuit (21) and an undercarriage circuit (22), which are connected to one another via a DC transmission (24) extending between the uppercarriage (14) and the undercarriage (12).

2. Construction machine (10) according to claim 1, wherein at least one electrical energy source is arranged in the superstructure (14) and comprises an electrical energy storage device (40).

3. Construction machine (10) according to one of the preceding claims, wherein at least one electrical energy source is arranged in the superstructure (14) and comprises a primary energy source (42), wherein the primary energy source preferably comprises an internal combustion engine (43) or a fuel cell.

4. Construction machine (10) according to one of the two preceding claims, wherein at least one electrical consumer (30) in the superstructure (14) can be supplied with energy via the superstructure circuit (21) and / or at least one electrical consumer (30) in the undercarriage (12) can be supplied with energy via the superstructure circuit (21), the direct current transmission (24) and the undercarriage circuit (22) from the electrical energy source (40, 42) arranged in the superstructure (14).

5. Construction machine (10) according to one of the preceding claims, wherein at least one electrical energy source is arranged in the undercarriage (12) and comprises an electrical energy storage device (40).

6. Construction machine (10) according to one of the preceding claims, wherein at least one electrical energy source is arranged in the undercarriage (12) and comprises a primary energy source (42).

7. Construction machine (10) according to one of the two preceding claims, wherein at least one electrical consumer (30) in the undercarriage (12) can be supplied with energy via the undercarriage circuit (22) and / or at least one electrical consumer (30) in the superstructure (14) can be supplied with energy via the undercarriage circuit (22), the direct current transmission (24) and the superstructure circuit (21) from the electrical energy source (40, 42) arranged in the undercarriage (12).

8. Construction machine (10) according to one of the preceding claims, wherein the undercarriage (12) comprises an electric travel drive with at least one electric travel motor, which can be supplied with energy via the superstructure circuit (21), the direct current transmission (24) and the undercarriage circuit (22) from an electrical energy source (40, 42) arranged in the superstructure (14).

9. Construction machine (10) according to one of the preceding claims, wherein the undercarriage (12) comprises at least one electrical consumer (30) in the form of an electric traction motor, wherein the electric traction motor preferably drives a wheel axle or a crawler track of the undercarriage.

10. Construction machine (10) according to the preceding claim, wherein the at least one electric traction motor is configured to supply an electrical consumer (30) and / or energy storage device (40) arranged in the undercarriage (12) with energy via the undercarriage circuit (22) in a recuperation mode and / or to supply an electrical consumer (30) and / or energy storage device (40) arranged in the superstructure (14) with energy via the undercarriage circuit (22), the direct current transmission (24) and the superstructure circuit (21).

11. Construction machine (10) according to one of the preceding claims, wherein the superstructure (14) comprises at least one electrical consumer (30) in the form of a low-voltage on-board network (34) and / or an electric motor (32), in particular for driving a hydraulic pump, a pump distribution gear, an actuator and / or a cooling device.

12. Construction machine (10) according to one of the preceding claims, wherein the undercarriage (12) comprises an electrical interface (50, 52) for connecting an external energy source (60), wherein at least one electrical consumer (30) or energy storage device (40) arranged in the superstructure (14) can be supplied with energy via the electrical interface (50, 52), the undercarriage circuit (22), the direct current transmission (24) and the superstructure circuit (21), wherein the electrical interface is preferably a direct current charging interface (50).

13. Construction machine (10) according to one of the preceding claims, wherein the direct current transmission (24) comprises a slip ring connection with a first slip ring contact connected to the undercarriage circuit (22), in particular first slip ring body, and a second slip ring contact, in particular a second slip ring body, connected to the superstructure circuit (21), wherein the slip ring connection is preferably arranged on or in a rotary connection between the superstructure and the undercarriage (12, 14).

14. Construction machine (10) according to one of the preceding claims, wherein the direct current transmission (24) is arranged for bidirectional direct current transmission between the undercarriage circuit (22) and the superstructure circuit (21).

15. Construction machine (10) according to one of the preceding claims, wherein the DC voltage circuit (24) is a high-voltage circuit, which in particular comprises at least one power electronics component (36, 38, 54), wherein the DC current transmission (24) is preferably designed for DC voltages of 60V to 1500V.

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