Construction machine with DC electrical system

Abstract

The invention relates to a construction machine comprising an undercarriage, a superstructure rotatably mounted on the undercarriage, and an electrical system. The electrical system comprises a DC circuit, at least one electrical load, and at least one electrical power source and / or interface for connecting an external power source, which are interconnected by the DC circuit. According to the invention, the DC circuit extends to the superstructure and the undercarriage and comprises a superstructure circuit and a substructure circuit, which are interconnected via a DC transmission line extending between the superstructure and the substructure.

Description

[0001] The present invention relates to a construction machine according to the preamble of claim 1.

[0002] In recent years, the trend towards the electrification of construction machinery has intensified, aiming to reduce CO2 emissions and increase energy security. This electrification has led to an increasing use of construction machinery with battery-electric or hybrid drive systems.

[0003] The typical structure of a known battery-electric or hybrid construction machine 1 is shown schematically in the Fig. Figure 1 illustrates the construction machine 1. It has an electrical energy source in the form of an electrical energy storage device 40, which is connected via a DC electrical system 20 to any number of electrical consumers 30. The electrical consumers 30 on the construction machine 1 can be several electric drive trains, each with at least one electric motor 32, which, for example, drive a pump distribution gearbox to supply hydraulic actuators and / or motors. A low-voltage electrical system 34, if present, can also be considered an electrical consumer 30. The construction machine 1 may also have additional power electronics, such as a DC / DC converter 38, which converts the DC intermediate circuit voltage into a low voltage (e.g., 24 V) for the low-voltage electrical system 34, or inverters, which convert the DC intermediate circuit voltage into an AC voltage to operate one or more electric motors 32.

[0004] Construction machine 1 can have a charging interface for connecting an external power source. In the Fig. Figure 1 shows an AC charging interface 52 for connecting an external three-phase electrical network 60, whereby the alternating voltage is converted into a suitable direct voltage for the DC intermediate circuit 20 via an AC / DC converter 54 (for example, a charger or on-board charger (OBC)).

[0005] In electro-hydraulic drive architectures, the electrical system is typically limited to an electric drivetrain, the main electric drive. This drives one or more hydraulic pumps via a transfer case. If, as in the Fig. As shown in Figure 1, where the respective load is driven directly by an electric machine, the DC electrical system 20 extends over the entire construction machine 1.

[0006] In the Fig. In the example shown, the construction machine 1 can have a primary energy source 42 in parallel with the energy storage device 40 (hybrid drive). The primary energy source 42 can comprise an internal combustion engine 43 (e.g., a diesel engine) that drives an electric generator 44, whose AC output voltage is converted into a suitable DC voltage for the DC intermediate circuit 20 by means of an AC / DC converter 45. The DC electrical system 20 connects the various electrical energy sources to the various electrical consumers and thus forms a DC intermediate circuit 20. In many construction machines, the DC intermediate circuit 20 forms a high-voltage electrical system, which is designed, for example, for DC voltages from 60 V to 1500 V.

[0007] A number of construction machines have an undercarriage and a superstructure that is rotatably mounted on the undercarriage. The undercarriage can be stationary or mobile. Examples of mobile machines include crawler cranes, mobile cranes, hydraulic excavators, cable excavators, truck-mounted concrete pumps (where the superstructure typically includes a concrete placing boom), and civil engineering machines such as rotary drilling rigs, trench cutters or grabs, or vibratory hammers. Construction machines with crawler tracks, in particular, usually have hydraulic drive systems. Typically, a diesel engine is located in the superstructure, which drives a pump distribution gearbox that supplies the hydraulic drive systems in the undercarriage. Alternatively, it is known to use a generator connected to the diesel engine to power an electric motor, which in turn drives a pump distribution gearbox to supply the hydraulic drive systems.

[0008] The present invention is based on the objective of enabling further electrification of construction machinery with a rotating superstructure.

[0009] According to the invention, this problem is solved by a construction machine with the features of claim 1. Advantageous embodiments of the invention are described in the dependent claims and the following description.

[0010] Accordingly, a construction machine is proposed, comprising an undercarriage, a superstructure rotatably mounted on the undercarriage, and an electrical system. The electrical system can be understood to mean, in particular, all the electrical components of the construction machine. The electrical system includes a DC circuit, at least one electrical load, and at least one electrical power source and / or at least one electrical interface for connecting an external power source. The at least one electrical load is connected to the at least one electrical power source and / or the at least one electrical interface via the DC circuit.The electrical system can also include, for example, a low-voltage 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.

[0011] According to the invention, the DC circuit extends to both the superstructure and the undercarriage and comprises a superstructure circuit arranged in the superstructure and a undercarriage circuit arranged in the undercarriage. For this purpose, the DC circuit includes a DC transmission line that extends between the superstructure and the undercarriage and connects the superstructure circuit to the undercarriage circuit, i.e., electrically connects them.

[0012] The solution according to the invention thus extends the DC electrical system, which is usually located in the superstructure, to the undercarriage, with direct current being transferred between the superstructure and undercarriage via the DC transmission system. This makes it possible, for example, to provide a purely electric drive system in the undercarriage, which is supplied 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 superstructure allows for the 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 avoided. For example, because the DC circuit now extends across the entire construction machine, it is possible to provide a DC charging interface on the undercarriage to charge an energy storage device in the superstructure. The supplied energy can then be made available via DC transmission to energy storage devices and / or consumers throughout the construction machine.

[0014] In the following, the terms “direct current” and “alternating current” or “direct voltage” and “alternating voltage” are also abbreviated as “DC” and “AC” (for example, “DC circuit” instead of “direct voltage circuit” or “DC transmission” instead of “direct current transmission”).

[0015] 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. The electrical energy storage device can supply energy to one or more electrical consumers of the construction machine. The at least one electrical energy storage device is preferably a battery-based energy storage device.

[0016] In another possible embodiment, the superstructure comprises at least one electrical energy source, which is a primary energy source. Unlike an electrical energy storage device, the primary energy source generates electrical energy itself and can, for example, comprise an internal combustion engine (e.g., a diesel or gasoline engine). This engine can be connected to an electric generator for generating electricity, the latter being coupled to the DC circuit, in particular via an AC / DC converter, to provide the required DC voltage. Alternatively, the primary energy source can comprise a fuel cell, which may optionally be coupled to the DC circuit via a DC / DC converter. Other primary energy sources, such as a solar power system or a wind turbine, are also conceivable.The upper structure can have several different primary energy sources, such as an internal combustion engine and a fuel cell.

[0017] Naturally, the upper structure can include multiple electrical energy sources, for example one or more electrical energy storage devices and one or more of the aforementioned primary energy sources, in any combination and number.

[0018] In another possible embodiment, the superstructure comprises at least one electrical load which can be supplied with energy from an electrical power source also located in or on the superstructure via the superstructure circuit. Alternatively or additionally, the undercarriage can comprise at least one electrical load which can be supplied with energy from an electrical power source located in or on the superstructure via the superstructure circuit, the DC transmission, and the undercarriage circuit.

[0019] Direct current (DC) transmission between the superstructure and undercarriage allows any electrical consumers in the superstructure and / or undercarriage to be powered by electrical energy sources in the superstructure, for example, an electric drive train for a working function of the superstructure and / or an electric traction drive in the undercarriage. Furthermore, energy transfer between electrical energy storage devices in the superstructure and electrical energy storage devices in the undercarriage is possible, for example, to recharge a depleted energy storage device via another, fuller energy storage device.

[0020] 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 preceding descriptions of the possible configurations of the electrical energy storage device of the superstructure apply analogously.

[0021] In another possible embodiment, the undercarriage comprises at least one electrical energy source, wherein the electrical energy source is a primary energy source. The preceding descriptions regarding a primary energy source of the superstructure also apply if the undercarriage has a primary energy source. The preceding descriptions 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.

[0022] In a preferred embodiment, the undercarriage has no primary power source or, more generally, no electrical power source of its own. In this case, all electrical consumers of the undercarriage (in particular one or more electric traction motors) are supplied via the DC transmission by one or more electrical power sources of the superstructure.

[0023] In another possible embodiment, the undercarriage comprises at least one electrical load which can be supplied with energy via the undercarriage from an electrical power source also located in or on the undercarriage. Alternatively or additionally, the superstructure can comprise at least one electrical load which can be supplied with energy via the undercarriage circuit, the DC transmission, and the superstructure circuit from an electrical power source located in or on the undercarriage. The DC transmission between the superstructure and undercarriage allows any electrical loads in the superstructure and / or the undercarriage to be supplied by electrical power sources in the undercarriage, for example, an electric drive train for a working function of the superstructure and / or an electric drive system in the undercarriage.Furthermore, energy transfer between electrical energy storage devices in the upper carriage and electrical energy storage devices in the undercarriage is possible.

[0024] In another possible embodiment, the undercarriage includes an electric drive system with at least one electric drive motor, which can be supplied with energy via the superstructure circuit, the DC transmission, and the undercarriage circuit from an electrical power source located in the superstructure. Optionally, the electric drive system can also be supplied via the undercarriage circuit by an electrical power source located in the undercarriage. Supply from power sources in the superstructure and the undercarriage can occur in parallel. Alternatively, a control unit can be provided which, depending on the operating state and / or user input, supplies the electric drive system either from the superstructure and / or from the undercarriage.

[0025] In another possible embodiment, the undercarriage includes at least one electrical consumer in the form of an electric drive motor, wherein the electric drive motor preferably drives a wheel axle or a track carrier of the undercarriage. In the case of an undercarriage with a tracked undercarriage, each track carrier can be driven by at least one separate electric drive motor.

[0026] In another possible embodiment, the at least one electric drive motor is configured to generate energy during recuperation (e.g., during braking of the construction machine), which can then be fed into the DC circuit. For example, the at least one electric drive motor can be configured to supply energy to at least one electrical consumer and / or at least one electrical energy storage device located in the undercarriage via the undercarriage circuit during recuperation. Alternatively or additionally, the at least one electric drive motor can be configured to supply energy to at least one electrical consumer and / or at least one electrical energy storage device located in the superstructure via the undercarriage circuit, DC transmission, and superstructure circuit during recuperation.

[0027] Regardless of the specific embodiment, the construction machine may preferably include 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 drive to an electrical energy storage device and / or an electrical energy source in the aforementioned recuperation operation.

[0028] In another possible embodiment, the superstructure includes at least one electrical consumer in the form of a low-voltage electrical system. This could be, for example, a 12V or 24V system, although a system with any other voltage is also possible. It is also conceivable that the construction machine includes several low-voltage electrical systems with different voltages, for example, a 12V system and a 24V system.

[0029] Alternatively or additionally, the superstructure can include 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 gearbox (e.g., for supplying luffing and telescoping cylinders on a mobile crane, one or more winches, one or more hydraulic cylinders on a hydraulic excavator, etc.), an actuator, or a cooling device of the construction machine. The superstructure can include several such electrical consumers or electric drive trains, in any number and combination of the aforementioned functions.

[0030] In another possible embodiment, the undercarriage includes an electrical interface for connecting an external power source. This external power source could 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 AC or DC form is suitable.

[0031] 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 DC power 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.

[0032] Preferably, the electrical interface is a 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 track of the undercarriage. During mains operation, the movements of the undercarriage are generally less than those of the superstructure (e.g., during superstructure rotation), thus simplifying the connection of the external power supply. In particular, with a charging interface arranged on the superstructure, a plugged-in charging cable would move along with a rotational movement of the superstructure or drag on the ground and thus potentially be damaged. The DC charging interface allows supplied energy to be provided to the DC circuit, and compared to AC charging interfaces, this also offers the advantage that no machine-side chargers, such as onboard chargers (OBCs), are required.

[0033] 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 that the undercarriage includes several 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 its arrangement on the superstructure or undercarriage) via an AC / DC converter, in particular an onboard converter (OBC).

[0034] In another possible embodiment, the DC 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. Preferably, the DC slip ring connection includes 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 DC transmission between the superstructure and undercarriage regardless of the rotational position of the superstructure relative to the undercarriage. The DC transmission is therefore maintained even when the superstructure is rotated and at any angular position.

[0035] The DC slip ring connection is preferably arranged on or in a rotary joint between the upper and lower carriages of the construction machine. The rotary joint preferably comprises a slewing mechanism with at least one hydraulic or electric rotary drive. The latter preferably represents an electrical load (or, in the case of a hydraulic rotary drive, the electric motor that drives the associated hydraulic pump or pump distribution gearbox) that is supplied via the DC circuit.

[0036] In another possible embodiment, the DC transmission is configured for bidirectional DC transmission between the undercarriage circuit and the superstructure circuit. This allows DC transmission both from the superstructure to the undercarriage and vice versa. As a result, electrical energy sources and electrical energy sinks or consumers can be flexibly arranged on the construction machine and distributed between the undercarriage and superstructure as needed.

[0037] In another possible embodiment, the DC circuit is a high-voltage circuit. This can mean, in particular, that the DC voltage in the circuit can range 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 machinery.

[0038] In general, the DC circuit can include 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 switched-mode power supplies.

[0039] The direct current circuit forms, in particular, a DC intermediate circuit.

[0040] Further features, details and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. The figures show: Fig. 1: a schematic representation of the electrical system of a construction machine known from the prior art; and Fig. 2: a schematic representation of the electrical on-board network of the construction machine according to the invention in an exemplary embodiment.

[0041] The Fig. Figure 1 shows a schematic representation of the electrical system of an example of a known construction machine 1 and has already been described at the beginning. In this example, there is no superstructure, and the electrical consumers 30 are all supplied with energy from the available electrical energy sources via a DC circuit 20. In this example, there is a primary energy source 42, an electrical energy storage device 40, and an external energy source 60, which is connected to the DC circuit 20 via an electrical AC interface 52 and an AC / DC converter 54.

[0042] The Fig. 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 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.

[0043] Components that have the same reference symbols as components of the Fig. 1. represent identical components or components with the same function. In particular, the components in the Fig. 2 unspecified components 30, 42 have the same subcomponents as those of the Fig. 1. The statements made at the beginning of the description therefore also apply to the components of the Fig. 2 (e.g., with reference to the embodiment of the primary energy source 42 with combustion engine 43, generator 44 and AC / DC converter 45, the embodiment of the electrical consumer 30 with DC / DC converter 38 and low-voltage on-board network 34 and / or the embodiment of the electrical consumer 30 with DC / AC converter 36 and electric motor 32).

[0044] The superstructure 14 of the illustrated embodiment of the construction machine 10 according to the invention comprises several electrical consumers 30. At least one of these electrical consumers 30 can comprise an electric motor 32 that drives a pump distribution gearbox to supply one or more hydraulic actuators (not shown). Alternatively, the corresponding working functions can be driven directly by electric actuators (e.g., an electric rotary drive for a slewing mechanism 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 electrical system 34 (e.g., a 24V electrical system).

[0045] In the embodiment shown schematically here, the upper carriage 14 comprises two electrical energy sources: an electrical energy storage device 40 (for example, a battery-based 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 interconnected via a DC circuit 20, which in the embodiment discussed here is a high-voltage DC network designed, for example, for DC voltages in the range of 60–1500 V. The DC 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 electrical system 34, and / or an AC / DC converter 45 for connecting a generator 44 to a primary energy source 42.

[0046] In the embodiment shown here, the undercarriage 12 also has several electrical consumers 30 in the form of electric drive motors. The electric drive motors 30 can be used to drive crawler tracks of a crawler undercarriage of the undercarriage 12. In order to supply the electric drive motors 30 in the undercarriage 12 with DC current from the DC circuit 20, this extends from the superstructure 14 to the undercarriage 12 via a DC transmission 24 (this is shown in the Fig. 2 schematically represented as box 24 (and could also be referred to as the DC connection). This is specifically designed for a DC voltage of 60-1500 V, in accordance with the design of the DC circuit 20. The part of the DC circuit 20 located in the superstructure 14 is referred to herein as superstructure circuit 21 and is shown in the Fig. 2 schematically illustrated by a box 21. The part of the DC circuit 20 located in the undercarriage 12 is referred to herein as the undercarriage circuit 22 and is shown in the Fig. 2 schematically illustrated by a box 22. The upper carriage circuit 21 is connected to the lower carriage circuit 22 via the DC transmission 24.

[0047] Furthermore, the construction machine 10, as in the Fig. As indicated in Figure 2, the undercarriage 12 has an electrical charging interface 50 for connecting an external energy source 60. The interface 50 is preferably a DC charging interface for feeding DC energy into the DC circuit 20. This eliminates the need for additional components such as an on-board computer (OBC).

[0048] Direct current can be transferred from the superstructure circuit 21 to the undercarriage circuit 22 or vice versa via the DC transmission 24 (bidirectional DC transmission). The control of the corresponding energy flows can be carried out by a control unit (not shown). The DC transmission 24 between the relative rotating sections of the construction machine 10 (i.e., between the undercarriage 12 and the superstructure 14) can be effected by means of DC slip rings (not shown).

[0049] The machine configuration according to the invention with DC transmission 24 between upper and lower carriage 12, 14 offers several advantages with regard to the electrification of construction machinery: • Power electronic components in the undercarriage 12 of the construction machine 10 can be supplied with power. This enables, for example, - electrification of vehicle propulsion systems; - a reduction in cable lengths and additional AC slip ring transmitters through the construction of a local DC intermediate circuit in the undercarriage 12 (avoiding unnecessary interfaces). • DC charging interfaces 50 are possible on the undercarriage 12 (e.g. on a crawler track). This allows the supplied energy to be made available to the DC electrical system 20 in the undercarriage and superstructure 12, 14 via the DC transmission 24. - Charging interfaces are particularly suitable on the undercarriage 12 or a crawler carrier, since the range of motion on the undercarriage 12 is lower than on the superstructure 14 during mains operation. - DC charging interfaces 50 also offer the advantage that no machine-side chargers 54 (e.g. onboard charger, OBC) are required. List of reference symbols: 1 Construction machine (state of the art) 10 Construction machine 12 undercarriages 14 upper carriages 20 DC circuit 21 Upper carriage circle 22 Undercarriage circle 24 Direct current transmission 30 Electrical consumers 32 Electric motor 34 Low-voltage electrical system 36 DC / AC converters 38 DC / DC converters 40 Electrical energy storage 42 Primary energy source 43 Internal combustion engine 44 Electric Generator 45 AC / DC converters 50 DC charging interface 52 AC charging interface 54 AC / OC converters / OBC 60 External energy source

Claims

[1] Construction machine (10) comprising an undercarriage (12), a superstructure (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 interconnected by the DC voltage circuit (20), characterized by in that the DC voltage circuit (20) extends to the superstructure (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 superstructure (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, in particular a first slip ring body, connected to the undercarriage circuit (22) 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 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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